a-a a-b a-c a-t aaa aab aac aak aat aay ab- aba abb abc abk abt aby ac- aca acb acc ack act acy aka akb akc akk at- ata atb atc att ay- aya ayc ayk ayt baa bab bac bak bat bay bba bbb bbc bbk bbt bby bca bcb bcc bck bct bcy bka bkb bkc bkk bkt bta btb btc btk btt bty by- bya byc byk byt c-- caa cab cac cak cat cay cba cbb cbc cbk cbt cby cca ccb ccc cck cct cka ckb ckc ckt cky cta ctb ctc ctk ctt cty cya cyb cyc cyk cyt k-t ka- kaa kab kac kak kat kay kba kbb kbc kbk kca kcb kcc kck kct kkb kkc kkk kkt kky kta ktb ktc ktk ktt kya kyc kyt taa tab tac tak tat tay tba tbb tbc tbk tbt tca tcb tcc tck tct tka tkb tkc tkk tkt tky tta ttb ttc ttk ttt tty tya tyc tyt yaa yab yac yak yat yay ybc yby yca ycc ycy yka ykk yta ytc ytk ytt yyb yyc yyt yyy