a-a a-b aaa aab aad aan aay ab- aba abb abd abn aby ad- ada adb add adn ady an- ana anb and ann any ay- aya ayd ayn baa bab bad ban bay bba bbb bbd bbn bby bda bdb bdd bdy bna bnb bnd bnn by- bya byd byn daa dab dad dan day dba dbb dbd dbn dby dda ddb ddd ddn ddy dna dnb dnd dnn dny dy- dya dyb dyd dyn dyy naa nab nad nan nay nba nbb nbd nbn nda ndb ndd ndn ndy nna nnb nnn nya nyd nyn nyy yaa yab yad yan yay yby yda ydn ydy yna ynd ynn yny yyb yyy