a-a a-b aaa aab aae aag aan aas ab- aba abb abe abg abn abs aea aeb aee aeg aen aes ag- aga agb age agg agn ags an- ana anb ane ang ann ans as- asa asb ase asg asn ass baa bab bae bag ban bas bba bbb bbe bbg bbn bbs be- bea beb bee beg ben bes bga bgb bge bgg bgn bgs bna bnb bne bng bnn bns bsa bsb bse bsg bsn bss eaa eab eae eag ean eas eba ebb ebe ebg ebn ebs eea eeb eee eeg een ees ega egb ege egg egn egs en- ena enb ene eng enn ens es- esa esb ese esg esn ess gaa gab gae gag gan gas gba gbe gbg gbn gbs ge- gea geb gee geg gen ges gga ggb ggg ggn ggs gna gnb gne gnn gns gsa gsb gse gsg gsn gss naa nab nae nag nan nas nba nbb nbe nbg nbn nbs ne- nea neb nee neg nen nes nga ngb nge ngg ngn ngs nna nnb nne nng nnn nns nsa nsb nse nsg nsn nss saa sab sae sag san sas sba sbb sbe sbg sbn sbs se- sea seb see seg sen ses sga sgb sge sgg sgn sgs sna snb sne sng snn sns ss- ssa ssb sse ssg ssn sss