a-a a-b a-t aaa aab aak aas aat ab- aba abb abk abs abt aka akb akk aks as- asa asb ask ass ast at- ata atb ats att baa bab bak bas bat bba bbb bbk bbs bbt bka bkb bkk bks bkt bsa bsb bsk bss bst bta btb btk bts btt k-t ka- kaa kab kak kas kat kba kbb kbk kbs kkb kkk kks kkt ksa ksb ksk kss kst kta ktb ktk kts ktt saa sab sak sas sat sba sbb sbk sbs sbt sk- ska skb skk sks skt ss- ssa ssb ssk sss sst sta stb stk sts stt taa tab tak tas tat tba tbb tbk tbs tbt tka tkb tkk tks tkt tsa tsb tsk tss tst tta ttb ttk tts ttt