a-a a-b a-i aaa aab aai aak aay ab- aba abb abi abk aby ai- aia aib aii aik aiy aka akb aki akk ay- aya ayi ayk baa bab bai bak bay bba bbb bbi bbk bby bi- bia bib bii bik biy bka bkb bkk by- bya byi byk ia- iaa iab iai iba ibb ibi ibk iby iia iib iii ika ikb iki ikk iya iyy ka- kaa kab kai kak kay kba kbb kbi kbk kia kib kii kik kkb kki kkk kky kya yaa yab yai yak yay ybi yby yii yka yki ykk yyb yyy