a-a a-b a-c a-t aaa aab aac aat aau aay ab- aba abb abc abt abu aby ac- aca acb acc act acu acy at- ata atb atc att atu au- aua aub auc aut ay- aya ayc ayt ayu b-u baa bab bac bat bau bay bba bbb bbc bbt bbu bby bca bcb bcc bct bcu bcy bta btb btc btt btu bty bua bub buc but buu buy by- bya byc byt byu c-- caa cab cac cat cau cay cba cbb cbc cbt cbu cby cca ccb ccc cct ccu cta ctb ctc ctt ctu cty cua cub cuc cut cuu cuy cya cyb cyc cyt taa tab tac tat tau tay tba tbb tbc tbt tbu tca tcb tcc tct tcu tta ttb ttc ttt ttu tty tua tub tuc tut tuu tuy tya tyc tyt ua- uaa uab uac uat uau uay uba ubb ubc ubt ubu uby uca ucb ucc uct ucu uta utb utc utt utu uty uua uuc uut uuu uyc uyu yaa yab yac yat yau yay ybc yby yca ycc ycu ycy yta ytc ytt ytu yua yut yuu yuy yyb yyc yyt yyu yyy