a-a a-b aaa aab aag aan aas ab- aba abb abg abn abs ag- aga agb agg agn ags an- ana anb ang ann ans as- asa asb asg asn ass baa bab bag ban bas bba bbb bbg bbn bbs bga bgb bgg bgn bgs bna bnb bng bnn bns bsa bsb bsg bsn bss gaa gab gag gan gas gba gbg gbn gbs gga ggb ggg ggn ggs gna gnb gnn gns gsa gsb gsg gsn gss naa nab nag nan nas nba nbb nbg nbn nbs nga ngb ngg ngn ngs nna nnb nng nnn nns nsa nsb nsg nsn nss saa sab sag san sas sba sbb sbg sbn sbs sga sgb sgg sgn sgs sna snb sng snn sns ss- ssa ssb ssg ssn sss