a-a a-b a-i a-t aaa aab aai aak aas aat ab- aba abb abi abk abs abt ai- aia aib aii aik ais ait aka akb aki akk aks as- asa asb asi ask ass ast at- ata atb ati ats att baa bab bai bak bas bat bba bbb bbi bbk bbs bbt bi- bia bib bii bik bis bit bka bkb bkk bks bkt bsa bsb bsi bsk bss bst bta btb bti btk bts btt ia- iaa iab iai ias iat iba ibb ibi ibk ibs ibt iia iib iii iis iit ika ikb iki ikk iks ikt is- isa isb isi isk iss ist ita itb iti itk its itt k-t ka- kaa kab kai kak kas kat kba kbb kbi kbk kbs kia kib kii kik kis kit kkb kki kkk kks kkt ksa ksb ksi ksk kss kst kta ktb ktk kts ktt saa sab sai sak sas sat sba sbb sbi sbk sbs sbt sia sib sii sik sis sit sk- ska skb ski skk sks skt ss- ssa ssb ssi ssk sss sst sta stb sti stk sts stt taa tab tai tak tas tat tba tbb tbi tbk tbs tbt tia tib tii tik tis tit tka tkb tkk tks tkt tsa tsb tsi tsk tss tst tta ttb tti ttk tts ttt