beta-D-GlcpNAc-(1->4)-beta-?-MurpNAc-(1->4)-beta-D-GlcpNAc-(1->4)-beta-?-MurpNAc-(1->4)-beta-D-GlcpNAc-(1->4)-beta-?-MurpNAc-(1->4)-beta-D-GlcpNAc-(1->4)-beta-?-MurpNAc(1->