a-a a-b a-i a-t aaa aab aai aas aat aay ab- aba abb abi abs abt aby ai- aia aib aii ais ait aiy as- asa asb asi ass ast asy at- ata atb ati ats att ay- aya ayi ays ayt baa bab bai bas bat bay bba bbb bbi bbs bbt bby bi- bia bib bii bis bit biy bsa bsb bsi bss bst bsy bta btb bti bts btt bty by- bya byi bys byt ia- iaa iab iai ias iat iba ibb ibi ibs ibt iby iia iib iii iis iit is- isa isb isi iss ist isy ita itb iti its itt ity iya iys iyt iyy saa sab sai sas sat say sba sbb sbi sbs sbt sby sia sib sii sis sit ss- ssa ssb ssi sss sst sta stb sti sts stt sty sy- sya syb syi sys syt taa tab tai tas tat tay tba tbb tbi tbs tbt tia tib tii tis tit tiy tsa tsb tsi tss tst tsy tta ttb tti tts ttt tty tya tys tyt yaa yab yai yas yat yay ybi ybs yby yii yis yit ysa ysb ysi yss yst ysy yta yts ytt yyb yys yyt yyy