?-D-NeupAc-(2->?)-?-D-Galp-(1->?)-?-D-GlcpNAc-(1->?)[?-D-NeupAc-(2->?)]-?-D-Galp-(1->?)-?-D-GlcpNAc-(1->?)[?-D-NeupAc-(2->?)]-D-GalNAc(?->