diff --git a/v2/accounting/marshal.go b/v2/accounting/marshal.go
index a0d73b1b..83fd0e7f 100644
--- a/v2/accounting/marshal.go
+++ b/v2/accounting/marshal.go
@@ -62,11 +62,9 @@ func (b *BalanceRequestBody) StableMarshal(buf []byte) ([]byte, error) {
 		buf = make([]byte, b.StableSize())
 	}
 
-	if b.ownerID != nil {
-		_, err := proto.NestedStructureMarshal(balanceReqBodyOwnerField, buf, b.ownerID)
-		if err != nil {
-			return nil, err
-		}
+	_, err := proto.NestedStructureMarshal(balanceReqBodyOwnerField, buf, b.ownerID)
+	if err != nil {
+		return nil, err
 	}
 
 	return buf, nil
@@ -77,9 +75,7 @@ func (b *BalanceRequestBody) StableSize() (size int) {
 		return 0
 	}
 
-	if b.ownerID != nil {
-		size = proto.NestedStructureSize(balanceReqBodyOwnerField, b.ownerID)
-	}
+	size = proto.NestedStructureSize(balanceReqBodyOwnerField, b.ownerID)
 
 	return size
 }
@@ -93,11 +89,9 @@ func (br *BalanceResponseBody) StableMarshal(buf []byte) ([]byte, error) {
 		buf = make([]byte, br.StableSize())
 	}
 
-	if br.bal != nil {
-		_, err := proto.NestedStructureMarshal(balanceRespBodyDecimalField, buf, br.bal)
-		if err != nil {
-			return nil, err
-		}
+	_, err := proto.NestedStructureMarshal(balanceRespBodyDecimalField, buf, br.bal)
+	if err != nil {
+		return nil, err
 	}
 
 	return buf, nil
@@ -108,9 +102,7 @@ func (br *BalanceResponseBody) StableSize() (size int) {
 		return 0
 	}
 
-	if br.bal != nil {
-		size = proto.NestedStructureSize(balanceRespBodyDecimalField, br.bal)
-	}
+	size = proto.NestedStructureSize(balanceRespBodyDecimalField, br.bal)
 
 	return size
 }
diff --git a/v2/acl/marshal.go b/v2/acl/marshal.go
index 7b9e7eaa..e596c0e8 100644
--- a/v2/acl/marshal.go
+++ b/v2/acl/marshal.go
@@ -1,8 +1,6 @@
 package acl
 
 import (
-	"encoding/binary"
-
 	"github.com/nspcc-dev/neofs-api-go/util/proto"
 )
 
@@ -37,34 +35,18 @@ func (t *Table) StableMarshal(buf []byte) ([]byte, error) {
 
 	var (
 		offset, n int
-		prefix    uint64
 		err       error
 	)
 
-	if t.cid != nil {
-		prefix, _ = proto.NestedStructurePrefix(tableContainerIDField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = t.cid.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = t.cid.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(tableContainerIDField, buf[offset:], t.cid)
+	if err != nil {
+		return nil, err
 	}
 
-	prefix, _ = proto.NestedStructurePrefix(tableRecordsField)
+	offset += n
 
 	for i := range t.records {
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = t.records[i].StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = t.records[i].StableMarshal(buf[offset:])
+		n, err = proto.NestedStructureMarshal(tableRecordsField, buf[offset:], t.records[i])
 		if err != nil {
 			return nil, err
 		}
@@ -81,17 +63,10 @@ func (t *Table) StableSize() (size int) {
 		return 0
 	}
 
-	if t.cid != nil {
-		_, ln := proto.NestedStructurePrefix(tableContainerIDField)
-		n := t.cid.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	_, ln := proto.NestedStructurePrefix(tableRecordsField)
+	size += proto.NestedStructureSize(tableContainerIDField, t.cid)
 
 	for i := range t.records {
-		n := t.records[i].StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
+		size += proto.NestedStructureSize(tableRecordsField, t.records[i])
 	}
 
 	return size
@@ -110,11 +85,10 @@ func (r *Record) StableMarshal(buf []byte) ([]byte, error) {
 
 	var (
 		offset, n int
-		prefix    uint64
 		err       error
 	)
 
-	n, err = proto.EnumMarshal(recordOperationField, buf, int32(r.op))
+	n, err = proto.EnumMarshal(recordOperationField, buf[offset:], int32(r.op))
 	if err != nil {
 		return nil, err
 	}
@@ -128,15 +102,8 @@ func (r *Record) StableMarshal(buf []byte) ([]byte, error) {
 
 	offset += n
 
-	prefix, _ = proto.NestedStructurePrefix(recordFiltersField)
-
 	for i := range r.filters {
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = r.filters[i].StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.filters[i].StableMarshal(buf[offset:])
+		n, err = proto.NestedStructureMarshal(recordFiltersField, buf[offset:], r.filters[i])
 		if err != nil {
 			return nil, err
 		}
@@ -144,15 +111,8 @@ func (r *Record) StableMarshal(buf []byte) ([]byte, error) {
 		offset += n
 	}
 
-	prefix, _ = proto.NestedStructurePrefix(recordTargetsField)
-
 	for i := range r.targets {
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = r.targets[i].StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.targets[i].StableMarshal(buf[offset:])
+		n, err = proto.NestedStructureMarshal(recordTargetsField, buf[offset:], r.targets[i])
 		if err != nil {
 			return nil, err
 		}
@@ -172,18 +132,12 @@ func (r *Record) StableSize() (size int) {
 	size += proto.EnumSize(recordOperationField, int32(r.op))
 	size += proto.EnumSize(recordActionField, int32(r.op))
 
-	_, ln := proto.NestedStructurePrefix(recordFiltersField)
-
 	for i := range r.filters {
-		n := r.filters[i].StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
+		size += proto.NestedStructureSize(recordFiltersField, r.filters[i])
 	}
 
-	_, ln = proto.NestedStructurePrefix(recordTargetsField)
-
 	for i := range r.targets {
-		n := r.targets[i].StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
+		size += proto.NestedStructureSize(recordTargetsField, r.targets[i])
 	}
 
 	return size
@@ -205,7 +159,7 @@ func (f *HeaderFilter) StableMarshal(buf []byte) ([]byte, error) {
 		err       error
 	)
 
-	n, err = proto.EnumMarshal(filterHeaderTypeField, buf, int32(f.hdrType))
+	n, err = proto.EnumMarshal(filterHeaderTypeField, buf[offset:], int32(f.hdrType))
 	if err != nil {
 		return nil, err
 	}
@@ -264,7 +218,7 @@ func (t *TargetInfo) StableMarshal(buf []byte) ([]byte, error) {
 		err       error
 	)
 
-	n, err = proto.EnumMarshal(targetTypeField, buf, int32(t.target))
+	n, err = proto.EnumMarshal(targetTypeField, buf[offset:], int32(t.target))
 	if err != nil {
 		return nil, err
 	}
diff --git a/v2/refs/marshal.go b/v2/refs/marshal.go
index 2a835fdb..40185008 100644
--- a/v2/refs/marshal.go
+++ b/v2/refs/marshal.go
@@ -1,20 +1,18 @@
 package refs
 
 import (
-	"encoding/binary"
-
 	"github.com/nspcc-dev/neofs-api-go/util/proto"
 )
 
 const (
-	OwnerIDValField = 1
+	ownerIDValField = 1
 
-	ContainerIDValField = 1
+	containerIDValField = 1
 
-	ObjectIDValField = 1
+	objectIDValField = 1
 
-	AddressContainerField = 1
-	AddressObjectField    = 2
+	addressContainerField = 1
+	addressObjectField    = 2
 )
 
 func (o *OwnerID) StableMarshal(buf []byte) ([]byte, error) {
@@ -26,7 +24,7 @@ func (o *OwnerID) StableMarshal(buf []byte) ([]byte, error) {
 		buf = make([]byte, o.StableSize())
 	}
 
-	_, err := proto.BytesMarshal(OwnerIDValField, buf, o.val)
+	_, err := proto.BytesMarshal(ownerIDValField, buf, o.val)
 	if err != nil {
 		return nil, err
 	}
@@ -38,7 +36,8 @@ func (o *OwnerID) StableSize() int {
 	if o == nil {
 		return 0
 	}
-	return proto.BytesSize(OwnerIDValField, o.val)
+
+	return proto.BytesSize(ownerIDValField, o.val)
 }
 
 func (c *ContainerID) StableMarshal(buf []byte) ([]byte, error) {
@@ -50,7 +49,7 @@ func (c *ContainerID) StableMarshal(buf []byte) ([]byte, error) {
 		buf = make([]byte, c.StableSize())
 	}
 
-	_, err := proto.BytesMarshal(ContainerIDValField, buf, c.val)
+	_, err := proto.BytesMarshal(containerIDValField, buf, c.val)
 	if err != nil {
 		return nil, err
 	}
@@ -62,7 +61,8 @@ func (c *ContainerID) StableSize() int {
 	if c == nil {
 		return 0
 	}
-	return proto.BytesSize(ContainerIDValField, c.val)
+
+	return proto.BytesSize(containerIDValField, c.val)
 }
 
 func (o *ObjectID) StableMarshal(buf []byte) ([]byte, error) {
@@ -74,7 +74,7 @@ func (o *ObjectID) StableMarshal(buf []byte) ([]byte, error) {
 		buf = make([]byte, o.StableSize())
 	}
 
-	_, err := proto.BytesMarshal(ObjectIDValField, buf, o.val)
+	_, err := proto.BytesMarshal(objectIDValField, buf, o.val)
 	if err != nil {
 		return nil, err
 	}
@@ -87,7 +87,7 @@ func (o *ObjectID) StableSize() int {
 		return 0
 	}
 
-	return proto.BytesSize(ObjectIDValField, o.val)
+	return proto.BytesSize(objectIDValField, o.val)
 }
 
 func (a *Address) StableMarshal(buf []byte) ([]byte, error) {
@@ -101,36 +101,19 @@ func (a *Address) StableMarshal(buf []byte) ([]byte, error) {
 
 	var (
 		offset, n int
-		prefix    uint64
 		err       error
 	)
 
-	if a.cid != nil {
-		prefix, _ = proto.NestedStructurePrefix(AddressContainerField)
-		offset = binary.PutUvarint(buf, prefix)
-
-		n = a.cid.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = a.cid.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(addressContainerField, buf[offset:], a.cid)
+	if err != nil {
+		return nil, err
 	}
 
-	if a.oid != nil {
-		prefix, _ = proto.NestedStructurePrefix(AddressObjectField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = a.oid.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = a.oid.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-		}
+	_, err = proto.NestedStructureMarshal(addressObjectField, buf[offset:], a.oid)
+	if err != nil {
+		return nil, err
 	}
 
 	return buf, nil
@@ -141,17 +124,9 @@ func (a *Address) StableSize() (size int) {
 		return 0
 	}
 
-	if a.cid != nil {
-		_, ln := proto.NestedStructurePrefix(AddressContainerField)
-		n := a.cid.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
+	size += proto.NestedStructureSize(addressContainerField, a.cid)
 
-	if a.oid != nil {
-		_, ln := proto.NestedStructurePrefix(AddressObjectField)
-		n := a.oid.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
+	size += proto.NestedStructureSize(addressObjectField, a.oid)
 
 	return size
 }
diff --git a/v2/service/marshal.go b/v2/service/marshal.go
index 241b2921..f30c9dff 100644
--- a/v2/service/marshal.go
+++ b/v2/service/marshal.go
@@ -1,8 +1,6 @@
 package service
 
 import (
-	"encoding/binary"
-
 	"github.com/nspcc-dev/neofs-api-go/util/proto"
 )
 
@@ -78,7 +76,7 @@ func (s *Signature) StableMarshal(buf []byte) ([]byte, error) {
 		err       error
 	)
 
-	n, err = proto.BytesMarshal(signatureKeyField, buf, s.key)
+	n, err = proto.BytesMarshal(signatureKeyField, buf[offset:], s.key)
 	if err != nil {
 		return nil, err
 	}
@@ -118,7 +116,7 @@ func (v *Version) StableMarshal(buf []byte) ([]byte, error) {
 		err       error
 	)
 
-	n, err = proto.UInt32Marshal(versionMajorField, buf, v.major)
+	n, err = proto.UInt32Marshal(versionMajorField, buf[offset:], v.major)
 	if err != nil {
 		return nil, err
 	}
@@ -158,7 +156,7 @@ func (x *XHeader) StableMarshal(buf []byte) ([]byte, error) {
 		err       error
 	)
 
-	n, err = proto.StringMarshal(xheaderKeyField, buf, x.key)
+	n, err = proto.StringMarshal(xheaderKeyField, buf[offset:], x.key)
 	if err != nil {
 		return nil, err
 	}
@@ -198,7 +196,7 @@ func (l *TokenLifetime) StableMarshal(buf []byte) ([]byte, error) {
 		err       error
 	)
 
-	n, err = proto.UInt64Marshal(lifetimeExpirationField, buf, l.exp)
+	n, err = proto.UInt64Marshal(lifetimeExpirationField, buf[offset:], l.exp)
 	if err != nil {
 		return nil, err
 	}
@@ -243,29 +241,19 @@ func (c *ObjectSessionContext) StableMarshal(buf []byte) ([]byte, error) {
 
 	var (
 		offset, n int
-		prefix    uint64
 		err       error
 	)
 
-	n, err = proto.EnumMarshal(objectCtxVerbField, buf, int32(c.verb))
+	n, err = proto.EnumMarshal(objectCtxVerbField, buf[offset:], int32(c.verb))
 	if err != nil {
 		return nil, err
 	}
 
 	offset += n
 
-	if c.addr != nil {
-		prefix, _ = proto.NestedStructurePrefix(objectCtxAddressField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = c.addr.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = c.addr.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
+	_, err = proto.NestedStructureMarshal(objectCtxAddressField, buf[offset:], c.addr)
+	if err != nil {
+		return nil, err
 	}
 
 	return buf, nil
@@ -277,12 +265,7 @@ func (c *ObjectSessionContext) StableSize() (size int) {
 	}
 
 	size += proto.EnumSize(objectCtxVerbField, int32(c.verb))
-
-	if c.addr != nil {
-		_, ln := proto.NestedStructurePrefix(objectCtxAddressField)
-		n := c.addr.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
+	size += proto.NestedStructureSize(objectCtxAddressField, c.addr)
 
 	return size
 }
@@ -298,49 +281,30 @@ func (t *SessionTokenBody) StableMarshal(buf []byte) ([]byte, error) {
 
 	var (
 		offset, n int
-		prefix    uint64
 		err       error
 	)
 
-	n, err = proto.BytesMarshal(sessionTokenBodyIDField, buf, t.id)
+	n, err = proto.BytesMarshal(sessionTokenBodyIDField, buf[offset:], t.id)
 	if err != nil {
 		return nil, err
 	}
 
 	offset += n
 
-	if t.ownerID != nil {
-		prefix, _ = proto.NestedStructurePrefix(sessionTokenBodyOwnerField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = t.ownerID.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = t.ownerID.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(sessionTokenBodyOwnerField, buf[offset:], t.ownerID)
+	if err != nil {
+		return nil, err
 	}
 
-	if t.lifetime != nil {
-		prefix, _ = proto.NestedStructurePrefix(sessionTokenBodyLifetimeField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = t.lifetime.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = t.lifetime.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(sessionTokenBodyLifetimeField, buf[offset:], t.lifetime)
+	if err != nil {
+		return nil, err
 	}
 
+	offset += n
+
 	n, err = proto.BytesMarshal(sessionTokenBodyKeyField, buf[offset:], t.sessionKey)
 	if err != nil {
 		return nil, err
@@ -351,16 +315,9 @@ func (t *SessionTokenBody) StableMarshal(buf []byte) ([]byte, error) {
 	if t.ctx != nil {
 		switch v := t.ctx.(type) {
 		case *ObjectSessionContext:
-			prefix, _ = proto.NestedStructurePrefix(sessionTokenBodyObjectCtxField)
-			offset += binary.PutUvarint(buf[offset:], prefix)
-
-			n = v.StableSize()
-			offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-			_, err = v.StableMarshal(buf[offset:])
+			_, err = proto.NestedStructureMarshal(sessionTokenBodyObjectCtxField, buf[offset:], v)
 			if err != nil {
 				return nil, err
-
 			}
 		default:
 			panic("cannot marshal unknown session token context")
@@ -376,27 +333,14 @@ func (t *SessionTokenBody) StableSize() (size int) {
 	}
 
 	size += proto.BytesSize(sessionTokenBodyIDField, t.id)
-
-	if t.ownerID != nil {
-		_, ln := proto.NestedStructurePrefix(sessionTokenBodyOwnerField)
-		n := t.ownerID.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	if t.lifetime != nil {
-		_, ln := proto.NestedStructurePrefix(sessionTokenBodyLifetimeField)
-		n := t.lifetime.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
+	size += proto.NestedStructureSize(sessionTokenBodyOwnerField, t.ownerID)
+	size += proto.NestedStructureSize(sessionTokenBodyLifetimeField, t.lifetime)
 	size += proto.BytesSize(sessionTokenBodyKeyField, t.sessionKey)
 
 	if t.ctx != nil {
 		switch v := t.ctx.(type) {
 		case *ObjectSessionContext:
-			_, ln := proto.NestedStructurePrefix(sessionTokenBodyObjectCtxField)
-			n := v.StableSize()
-			size += ln + proto.VarUIntSize(uint64(n)) + n
+			size += proto.NestedStructureSize(sessionTokenBodyObjectCtxField, v)
 		default:
 			panic("cannot marshal unknown session token context")
 		}
@@ -416,38 +360,19 @@ func (t *SessionToken) StableMarshal(buf []byte) ([]byte, error) {
 
 	var (
 		offset, n int
-		prefix    uint64
 		err       error
 	)
 
-	if t.body != nil {
-		prefix, _ = proto.NestedStructurePrefix(sessionTokenBodyField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = t.body.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = t.body.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(sessionTokenBodyField, buf[offset:], t.body)
+	if err != nil {
+		return nil, err
 	}
 
-	if t.sig != nil {
-		prefix, _ = proto.NestedStructurePrefix(sessionTokenSignatureField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = t.sig.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = t.sig.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
+	_, err = proto.NestedStructureMarshal(sessionTokenSignatureField, buf[offset:], t.sig)
+	if err != nil {
+		return nil, err
 	}
 
 	return buf, nil
@@ -458,17 +383,8 @@ func (t *SessionToken) StableSize() (size int) {
 		return 0
 	}
 
-	if t.body != nil {
-		_, ln := proto.NestedStructurePrefix(sessionTokenBodyField)
-		n := t.body.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	if t.sig != nil {
-		_, ln := proto.NestedStructurePrefix(sessionTokenSignatureField)
-		n := t.sig.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
+	size += proto.NestedStructureSize(sessionTokenBodyField, t.body)
+	size += proto.NestedStructureSize(sessionTokenSignatureField, t.sig)
 
 	return size
 }
@@ -484,54 +400,26 @@ func (bt *BearerTokenBody) StableMarshal(buf []byte) ([]byte, error) {
 
 	var (
 		offset, n int
-		prefix    uint64
 		err       error
 	)
 
-	if bt.eacl != nil {
-		prefix, _ = proto.NestedStructurePrefix(bearerTokenBodyACLField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = bt.eacl.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = bt.eacl.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(bearerTokenBodyACLField, buf[offset:], bt.eacl)
+	if err != nil {
+		return nil, err
 	}
 
-	if bt.ownerID != nil {
-		prefix, _ = proto.NestedStructurePrefix(bearerTokenBodyOwnerField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = bt.ownerID.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = bt.ownerID.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(bearerTokenBodyOwnerField, buf[offset:], bt.ownerID)
+	if err != nil {
+		return nil, err
 	}
 
-	if bt.lifetime != nil {
-		prefix, _ = proto.NestedStructurePrefix(bearerTokenBodyLifetimeField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = bt.lifetime.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = bt.lifetime.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
+	_, err = proto.NestedStructureMarshal(bearerTokenBodyLifetimeField, buf[offset:], bt.lifetime)
+	if err != nil {
+		return nil, err
 	}
 
 	return buf, nil
@@ -542,23 +430,9 @@ func (bt *BearerTokenBody) StableSize() (size int) {
 		return 0
 	}
 
-	if bt.eacl != nil {
-		_, ln := proto.NestedStructurePrefix(bearerTokenBodyACLField)
-		n := bt.eacl.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	if bt.ownerID != nil {
-		_, ln := proto.NestedStructurePrefix(bearerTokenBodyOwnerField)
-		n := bt.ownerID.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	if bt.lifetime != nil {
-		_, ln := proto.NestedStructurePrefix(bearerTokenBodyLifetimeField)
-		n := bt.lifetime.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
+	size += proto.NestedStructureSize(bearerTokenBodyACLField, bt.eacl)
+	size += proto.NestedStructureSize(bearerTokenBodyOwnerField, bt.ownerID)
+	size += proto.NestedStructureSize(bearerTokenBodyLifetimeField, bt.lifetime)
 
 	return size
 }
@@ -574,38 +448,19 @@ func (bt *BearerToken) StableMarshal(buf []byte) ([]byte, error) {
 
 	var (
 		offset, n int
-		prefix    uint64
 		err       error
 	)
 
-	if bt.body != nil {
-		prefix, _ = proto.NestedStructurePrefix(bearerTokenBodyField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = bt.body.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = bt.body.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(bearerTokenBodyField, buf[offset:], bt.body)
+	if err != nil {
+		return nil, err
 	}
 
-	if bt.sig != nil {
-		prefix, _ = proto.NestedStructurePrefix(bearerTokenSignatureField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = bt.sig.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = bt.sig.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
+	_, err = proto.NestedStructureMarshal(bearerTokenSignatureField, buf[offset:], bt.sig)
+	if err != nil {
+		return nil, err
 	}
 
 	return buf, nil
@@ -616,17 +471,8 @@ func (bt *BearerToken) StableSize() (size int) {
 		return 0
 	}
 
-	if bt.body != nil {
-		_, ln := proto.NestedStructurePrefix(bearerTokenBodyField)
-		n := bt.body.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	if bt.sig != nil {
-		_, ln := proto.NestedStructurePrefix(bearerTokenSignatureField)
-		n := bt.sig.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
+	size += proto.NestedStructureSize(bearerTokenBodyField, bt.body)
+	size += proto.NestedStructureSize(bearerTokenSignatureField, bt.sig)
 
 	return size
 }
@@ -642,26 +488,16 @@ func (r *RequestMetaHeader) StableMarshal(buf []byte) ([]byte, error) {
 
 	var (
 		offset, n int
-		prefix    uint64
 		err       error
 	)
 
-	if r.version != nil {
-		prefix, _ = proto.NestedStructurePrefix(reqMetaHeaderVersionField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = r.version.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.version.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(reqMetaHeaderVersionField, buf[offset:], r.version)
+	if err != nil {
+		return nil, err
 	}
 
+	offset += n
+
 	n, err = proto.UInt64Marshal(reqMetaHeaderEpochField, buf[offset:], r.epoch)
 	if err != nil {
 		return nil, err
@@ -676,67 +512,32 @@ func (r *RequestMetaHeader) StableMarshal(buf []byte) ([]byte, error) {
 
 	offset += n
 
-	prefix, _ = proto.NestedStructurePrefix(reqMetaHeaderXHeadersField)
-
 	for i := range r.xHeaders {
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = r.xHeaders[i].StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.xHeaders[i].StableMarshal(buf[offset:])
+		n, err = proto.NestedStructureMarshal(reqMetaHeaderXHeadersField, buf[offset:], r.xHeaders[i])
 		if err != nil {
 			return nil, err
-
 		}
 
 		offset += n
 	}
 
-	if r.sessionToken != nil {
-		prefix, _ = proto.NestedStructurePrefix(reqMetaHeaderSessionTokenField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = r.sessionToken.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.sessionToken.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(reqMetaHeaderSessionTokenField, buf[offset:], r.sessionToken)
+	if err != nil {
+		return nil, err
 	}
 
-	if r.bearerToken != nil {
-		prefix, _ = proto.NestedStructurePrefix(reqMetaHeaderBearerTokenField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = r.bearerToken.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.bearerToken.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(reqMetaHeaderBearerTokenField, buf[offset:], r.bearerToken)
+	if err != nil {
+		return nil, err
 	}
 
-	if r.origin != nil {
-		prefix, _ = proto.NestedStructurePrefix(reqMetaHeaderOriginField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = r.origin.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.origin.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
+	_, err = proto.NestedStructureMarshal(reqMetaHeaderOriginField, buf[offset:], r.origin)
+	if err != nil {
+		return nil, err
 	}
 
 	return buf, nil
@@ -748,38 +549,19 @@ func (r *RequestMetaHeader) StableSize() (size int) {
 	}
 
 	if r.version != nil {
-		_, ln := proto.NestedStructurePrefix(reqMetaHeaderVersionField)
-		n := r.version.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
+		size += proto.NestedStructureSize(reqMetaHeaderVersionField, r.version)
 	}
 
 	size += proto.UInt64Size(reqMetaHeaderEpochField, r.epoch)
 	size += proto.UInt32Size(reqMetaHeaderTTLField, r.ttl)
 
-	_, ln := proto.NestedStructurePrefix(reqMetaHeaderXHeadersField)
-
 	for i := range r.xHeaders {
-		n := r.xHeaders[i].StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
+		size += proto.NestedStructureSize(reqMetaHeaderXHeadersField, r.xHeaders[i])
 	}
 
-	if r.sessionToken != nil {
-		_, ln := proto.NestedStructurePrefix(reqMetaHeaderSessionTokenField)
-		n := r.sessionToken.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	if r.bearerToken != nil {
-		_, ln := proto.NestedStructurePrefix(reqMetaHeaderBearerTokenField)
-		n := r.bearerToken.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	if r.origin != nil {
-		_, ln := proto.NestedStructurePrefix(reqMetaHeaderOriginField)
-		n := r.origin.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
+	size += proto.NestedStructureSize(reqMetaHeaderSessionTokenField, r.sessionToken)
+	size += proto.NestedStructureSize(reqMetaHeaderBearerTokenField, r.bearerToken)
+	size += proto.NestedStructureSize(reqMetaHeaderOriginField, r.origin)
 
 	return size
 }
@@ -795,70 +577,33 @@ func (r *RequestVerificationHeader) StableMarshal(buf []byte) ([]byte, error) {
 
 	var (
 		offset, n int
-		prefix    uint64
 		err       error
 	)
 
-	if r.bodySig != nil {
-		prefix, _ = proto.NestedStructurePrefix(reqVerifHeaderBodySignatureField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = r.bodySig.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.bodySig.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(reqVerifHeaderBodySignatureField, buf[offset:], r.bodySig)
+	if err != nil {
+		return nil, err
 	}
 
-	if r.metaSig != nil {
-		prefix, _ = proto.NestedStructurePrefix(reqVerifHeaderMetaSignatureField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = r.metaSig.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.metaSig.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(reqVerifHeaderMetaSignatureField, buf[offset:], r.metaSig)
+	if err != nil {
+		return nil, err
 	}
 
-	if r.originSig != nil {
-		prefix, _ = proto.NestedStructurePrefix(reqVerifHeaderOriginSignatureField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = r.originSig.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.originSig.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(reqVerifHeaderOriginSignatureField, buf[offset:], r.originSig)
+	if err != nil {
+		return nil, err
 	}
 
-	if r.origin != nil {
-		prefix, _ = proto.NestedStructurePrefix(reqVerifHeaderOriginField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = r.origin.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.origin.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
+	_, err = proto.NestedStructureMarshal(reqVerifHeaderOriginField, buf[offset:], r.origin)
+	if err != nil {
+		return nil, err
 	}
 
 	return buf, nil
@@ -869,29 +614,10 @@ func (r *RequestVerificationHeader) StableSize() (size int) {
 		return 0
 	}
 
-	if r.bodySig != nil {
-		_, ln := proto.NestedStructurePrefix(reqVerifHeaderBodySignatureField)
-		n := r.bodySig.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	if r.metaSig != nil {
-		_, ln := proto.NestedStructurePrefix(reqVerifHeaderMetaSignatureField)
-		n := r.metaSig.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	if r.originSig != nil {
-		_, ln := proto.NestedStructurePrefix(reqVerifHeaderOriginSignatureField)
-		n := r.originSig.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	if r.origin != nil {
-		_, ln := proto.NestedStructurePrefix(reqVerifHeaderOriginField)
-		n := r.origin.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
+	size += proto.NestedStructureSize(reqVerifHeaderBodySignatureField, r.bodySig)
+	size += proto.NestedStructureSize(reqVerifHeaderMetaSignatureField, r.metaSig)
+	size += proto.NestedStructureSize(reqVerifHeaderOriginSignatureField, r.originSig)
+	size += proto.NestedStructureSize(reqVerifHeaderOriginField, r.origin)
 
 	return size
 }
@@ -907,26 +633,16 @@ func (r *ResponseMetaHeader) StableMarshal(buf []byte) ([]byte, error) {
 
 	var (
 		offset, n int
-		prefix    uint64
 		err       error
 	)
 
-	if r.version != nil {
-		prefix, _ = proto.NestedStructurePrefix(respMetaHeaderVersionField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = r.version.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.version.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(respMetaHeaderVersionField, buf[offset:], r.version)
+	if err != nil {
+		return nil, err
 	}
 
+	offset += n
+
 	n, err = proto.UInt64Marshal(respMetaHeaderEpochField, buf[offset:], r.epoch)
 	if err != nil {
 		return nil, err
@@ -941,35 +657,18 @@ func (r *ResponseMetaHeader) StableMarshal(buf []byte) ([]byte, error) {
 
 	offset += n
 
-	prefix, _ = proto.NestedStructurePrefix(respMetaHeaderXHeadersField)
-
 	for i := range r.xHeaders {
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = r.xHeaders[i].StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.xHeaders[i].StableMarshal(buf[offset:])
+		n, err = proto.NestedStructureMarshal(respMetaHeaderXHeadersField, buf[offset:], r.xHeaders[i])
 		if err != nil {
 			return nil, err
-
 		}
 
 		offset += n
 	}
 
-	if r.origin != nil {
-		prefix, _ = proto.NestedStructurePrefix(respMetaHeaderOriginField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = r.origin.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.origin.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
+	_, err = proto.NestedStructureMarshal(respMetaHeaderOriginField, buf[offset:], r.origin)
+	if err != nil {
+		return nil, err
 	}
 
 	return buf, nil
@@ -981,26 +680,17 @@ func (r *ResponseMetaHeader) StableSize() (size int) {
 	}
 
 	if r.version != nil {
-		_, ln := proto.NestedStructurePrefix(respMetaHeaderVersionField)
-		n := r.version.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
+		size += proto.NestedStructureSize(respMetaHeaderVersionField, r.version)
 	}
 
 	size += proto.UInt64Size(respMetaHeaderEpochField, r.epoch)
 	size += proto.UInt32Size(respMetaHeaderTTLField, r.ttl)
 
-	_, ln := proto.NestedStructurePrefix(respMetaHeaderXHeadersField)
-
 	for i := range r.xHeaders {
-		n := r.xHeaders[i].StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
+		size += proto.NestedStructureSize(respMetaHeaderXHeadersField, r.xHeaders[i])
 	}
 
-	if r.origin != nil {
-		_, ln := proto.NestedStructurePrefix(respMetaHeaderOriginField)
-		n := r.origin.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
+	size += proto.NestedStructureSize(respMetaHeaderOriginField, r.origin)
 
 	return size
 }
@@ -1016,70 +706,33 @@ func (r *ResponseVerificationHeader) StableMarshal(buf []byte) ([]byte, error) {
 
 	var (
 		offset, n int
-		prefix    uint64
 		err       error
 	)
 
-	if r.bodySig != nil {
-		prefix, _ = proto.NestedStructurePrefix(respVerifHeaderBodySignatureField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = r.bodySig.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.bodySig.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(respVerifHeaderBodySignatureField, buf[offset:], r.bodySig)
+	if err != nil {
+		return nil, err
 	}
 
-	if r.metaSig != nil {
-		prefix, _ = proto.NestedStructurePrefix(respVerifHeaderMetaSignatureField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = r.metaSig.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.metaSig.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(respVerifHeaderMetaSignatureField, buf[offset:], r.metaSig)
+	if err != nil {
+		return nil, err
 	}
 
-	if r.originSig != nil {
-		prefix, _ = proto.NestedStructurePrefix(respVerifHeaderOriginSignatureField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = r.originSig.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.originSig.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
-
-		offset += n
+	n, err = proto.NestedStructureMarshal(respVerifHeaderOriginSignatureField, buf[offset:], r.originSig)
+	if err != nil {
+		return nil, err
 	}
 
-	if r.origin != nil {
-		prefix, _ = proto.NestedStructurePrefix(respVerifHeaderOriginField)
-		offset += binary.PutUvarint(buf[offset:], prefix)
+	offset += n
 
-		n = r.origin.StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = r.origin.StableMarshal(buf[offset:])
-		if err != nil {
-			return nil, err
-
-		}
+	_, err = proto.NestedStructureMarshal(respVerifHeaderOriginField, buf[offset:], r.origin)
+	if err != nil {
+		return nil, err
 	}
 
 	return buf, nil
@@ -1090,29 +743,10 @@ func (r *ResponseVerificationHeader) StableSize() (size int) {
 		return 0
 	}
 
-	if r.bodySig != nil {
-		_, ln := proto.NestedStructurePrefix(respVerifHeaderBodySignatureField)
-		n := r.bodySig.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	if r.metaSig != nil {
-		_, ln := proto.NestedStructurePrefix(respVerifHeaderMetaSignatureField)
-		n := r.metaSig.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	if r.originSig != nil {
-		_, ln := proto.NestedStructurePrefix(respVerifHeaderOriginSignatureField)
-		n := r.originSig.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
-
-	if r.origin != nil {
-		_, ln := proto.NestedStructurePrefix(respVerifHeaderOriginField)
-		n := r.origin.StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
-	}
+	size += proto.NestedStructureSize(respVerifHeaderBodySignatureField, r.bodySig)
+	size += proto.NestedStructureSize(respVerifHeaderMetaSignatureField, r.metaSig)
+	size += proto.NestedStructureSize(respVerifHeaderOriginSignatureField, r.originSig)
+	size += proto.NestedStructureSize(respVerifHeaderOriginField, r.origin)
 
 	return size
 }
diff --git a/v2/storagegroup/marshal.go b/v2/storagegroup/marshal.go
index 4f30d50a..cc1160f7 100644
--- a/v2/storagegroup/marshal.go
+++ b/v2/storagegroup/marshal.go
@@ -1,20 +1,14 @@
 package storagegroup
 
 import (
-	"encoding/binary"
-
 	"github.com/nspcc-dev/neofs-api-go/util/proto"
 )
 
 const (
-	// SizeField order number from storage group proto definition.
-	SizeField = 1
-	// HashField order number from storage group proto definition.
-	HashField = 2
-	// ExpirationField order number from storage group proto definition.
-	ExpirationField = 3
-	// ObjectIDsField order number from storage group proto definition.
-	ObjectIDsField = 4
+	sizeField       = 1
+	hashField       = 2
+	expirationField = 3
+	objectIDsField  = 4
 )
 
 // StableMarshal marshals unified storage group structure in a protobuf
@@ -30,40 +24,32 @@ func (s *StorageGroup) StableMarshal(buf []byte) ([]byte, error) {
 
 	var (
 		offset, n int
-		prefix    uint64
 		err       error
 	)
 
-	n, err = proto.UInt64Marshal(SizeField, buf, s.size)
+	n, err = proto.UInt64Marshal(sizeField, buf[offset:], s.size)
 	if err != nil {
 		return nil, err
 	}
 
 	offset += n
 
-	n, err = proto.BytesMarshal(HashField, buf[offset:], s.hash)
+	n, err = proto.BytesMarshal(hashField, buf[offset:], s.hash)
 	if err != nil {
 		return nil, err
 	}
 
 	offset += n
 
-	n, err = proto.UInt64Marshal(ExpirationField, buf[offset:], s.exp)
+	n, err = proto.UInt64Marshal(expirationField, buf[offset:], s.exp)
 	if err != nil {
 		return nil, err
 	}
 
 	offset += n
 
-	prefix, _ = proto.NestedStructurePrefix(ObjectIDsField)
-
 	for i := range s.members {
-		offset += binary.PutUvarint(buf[offset:], prefix)
-
-		n = s.members[i].StableSize()
-		offset += binary.PutUvarint(buf[offset:], uint64(n))
-
-		_, err = s.members[i].StableMarshal(buf[offset:])
+		n, err = proto.NestedStructureMarshal(objectIDsField, buf[offset:], s.members[i])
 		if err != nil {
 			return nil, err
 		}
@@ -80,15 +66,12 @@ func (s *StorageGroup) StableSize() (size int) {
 		return 0
 	}
 
-	size += proto.UInt64Size(SizeField, s.size)
-	size += proto.BytesSize(HashField, s.hash)
-	size += proto.UInt64Size(ExpirationField, s.exp)
-
-	_, ln := proto.NestedStructurePrefix(ObjectIDsField)
+	size += proto.UInt64Size(sizeField, s.size)
+	size += proto.BytesSize(hashField, s.hash)
+	size += proto.UInt64Size(expirationField, s.exp)
 
 	for i := range s.members {
-		n := s.members[i].StableSize()
-		size += ln + proto.VarUIntSize(uint64(n)) + n
+		size += proto.NestedStructureSize(objectIDsField, s.members[i])
 	}
 
 	return size