a-a a-b a-c aaa aab aac aag aak aan ab- aba abb abc abg abk abn ac- aca acb acc acg ack acn ag- aga agb agc agg agk agn aka akb akc akg akk akn an- ana anb anc ang ank ann baa bab bac bag bak ban bba bbb bbc bbg bbk bbn bca bcb bcc bcg bck bcn bga bgb bgc bgg bgk bgn bka bkb bkc bkg bkk bkn bna bnb bnc bng bnk bnn c-- caa cab cac cag cak can cba cbb cbc cbg cbk cbn cca ccb ccc ccg cck ccn cga cgb cgc cgg cgn cka ckb ckc cn- cna cnb cnc cng cnn gaa gab gac gag gak gan gba gbc gbg gbk gbn gca gcb gcc gcg gck gcn gga ggb ggc ggg ggn gka gkb gkn gna gnb gnc gnn ka- kaa kab kac kag kak kan kba kbb kbc kbk kbn kca kcb kcc kcg kck kcn kga kgb kgc kkb kkc kkk kkn kn- kna knc kng knk knn naa nab nac nag nak nan nba nbb nbc nbg nbk nbn nca ncb ncc ncg nck ncn nga ngb ngc ngg ngk ngn nka nkc nkk nkn nna nnb nnc nng nnk nnn