a-a a-b a-t aaa aab aak aat aay ab- aba abb abk abt aby aka akb akk at- ata atb att ay- aya ayk ayt baa bab bak bat bay bba bbb bbk bbt bby bka bkb bkk bkt bta btb btk btt bty by- bya byk byt k-t ka- kaa kab kak kat kay kba kbb kbk kkb kkk kkt kky kta ktb ktk ktt kya kyt taa tab tak tat tay tba tbb tbk tbt tka tkb tkk tkt tky tta ttb ttk ttt tty tya tyt yaa yab yak yat yay yby yka ykk yta ytk ytt yyb yyt yyy