a-a a-b a-c a-t aaa aab aac aak aas aat aay ab- aba abb abc abk abs abt aby ac- aca acb acc ack acs act acy aka akb akc akk aks as- asa asb asc ask ass ast asy at- ata atb atc ats att ay- aya ayc ayk ays ayt baa bab bac bak bas bat bay bba bbb bbc bbk bbs bbt bby bca bcb bcc bck bcs bct bcy bka bkb bkc bkk bks bkt bsa bsb bsc bsk bss bst bsy bta btb btc btk bts btt bty by- bya byc byk bys byt c-- caa cab cac cak cas cat cay cba cbb cbc cbk cbs cbt cby cca ccb ccc cck ccs cct cka ckb ckc cks ckt cky csa csb csc csk css cst csy cta ctb ctc ctk cts ctt cty cya cyb cyc cyk cys cyt k-t ka- kaa kab kac kak kas kat kay kba kbb kbc kbk kbs kca kcb kcc kck kcs kct kkb kkc kkk kks kkt kky ksa ksb ksc ksk kss kst kta ktb ktc ktk kts ktt kya kyc kys kyt saa sab sac sak sas sat say sba sbb sbc sbk sbs sbt sby sca scb scc sck scs sct sk- ska skb skc skk sks skt sky ss- ssa ssb ssc ssk sss sst sta stb stc stk sts stt sty sy- sya syb syc syk sys syt taa tab tac tak tas tat tay tba tbb tbc tbk tbs tbt tca tcb tcc tck tcs tct tka tkb tkc tkk tks tkt tky tsa tsb tsc tsk tss tst tsy tta ttb ttc ttk tts ttt tty tya tyc tys tyt yaa yab yac yak yas yat yay ybc ybs yby yca ycc ycs ycy yka ykk ysa ysb ysc ysk yss yst ysy yta ytc ytk yts ytt yyb yyc yys yyt yyy