a-a a-b aaa aab aag aak aan ab- aba abb abg abk abn ag- aga agb agg agk agn aka akb akg akk akn an- ana anb ang ank ann baa bab bag bak ban bba bbb bbg bbk bbn bga bgb bgg bgk bgn bka bkb bkg bkk bkn bna bnb bng bnk bnn gaa gab gag gak gan gba gbg gbk gbn gga ggb ggg ggn gka gkb gkn gna gnb gnn ka- kaa kab kag kak kan kba kbb kbk kbn kga kgb kkb kkk kkn kn- kna kng knk knn naa nab nag nak nan nba nbb nbg nbk nbn nga ngb ngg ngk ngn nka nkk nkn nna nnb nng nnk nnn