a-a a-b a-i a-t aaa aab aai aat aay ab- aba abb abi abt aby ai- aia aib aii ait aiy at- ata atb ati att ay- aya ayi ayt baa bab bai bat bay bba bbb bbi bbt bby bi- bia bib bii bit biy bta btb bti btt bty by- bya byi byt ia- iaa iab iai iat iba ibb ibi ibt iby iia iib iii iit ita itb iti itt ity iya iyt iyy taa tab tai tat tay tba tbb tbi tbt tia tib tii tit tiy tta ttb tti ttt tty tya tyt yaa yab yai yat yay ybi yby yii yit yta ytt yyb yyt yyy