a-a a-b aaa aab aak aam aan ab- aba abb abk abm abn aka akb akk akm akn ama amb amk amm amn an- ana anb ank anm ann baa bab bak bam ban bba bbb bbk bbm bbn bka bkb bkk bkm bkn bma bmb bmk bmm bmn bna bnb bnk bnn ka- kaa kab kak kam kan kba kbb kbk kbm kbn kkb kkk kkm kkn kma kmb kmk kmm kn- kna knk knm knn maa mab mak mam man mba mbb mbk mbm mka mkb mkk mkm mkn mma mmb mmk mmm mmn mna mnb mnk mnm mnn naa nab nak nam nan nba nbb nbk nbm nbn nka nkk nkm nkn nma nmb nmk nmm nmn nna nnb nnk nnm nnn