a-a a-b aaa aab aaf aak aam ab- aba abb abf abk abm af- afa afb aff afk afm aka akb akk akm ama amb amf amk amm baa bab baf bak bam bba bbb bbf bbk bbm bfa bfb bff bfm bka bkb bkf bkk bkm bma bmb bmf bmk bmm faa fab faf fak fam fba fbb fbf fbk fbm ffa fff ffk ffm fka fkb fkf fkk fkm fma fmb fmf fmm ka- kaa kab kaf kak kam kba kbb kbf kbk kbm kfa kff kfm kkb kkk kkm kma kmb kmf kmk kmm m-f maa mab maf mak mam mba mbb mbf mbk mbm mfa mfb mff mfm mka mkb mkk mkm mma mmb mmf mmk mmm