a-a a-b a-c a-z aaa aab aac aan aay aaz ab- aba abb abc abn aby abz ac- aca acb acc acn acy acz an- ana anb anc ann any anz ay- aya ayc ayn ayz az- aza azb azn azy azz baa bab bac ban bay baz bba bbb bbc bbn bby bca bcb bcc bcn bcy bcz bna bnb bnc bnn bnz by- bya byc byn byz bza bzn bzz c-- caa cab cac can cay caz cba cbb cbc cbn cby cbz cca ccb ccc ccn ccz cn- cna cnb cnc cnn cny cya cyb cyc cyn cz- czc naa nab nac nan nay naz nba nbb nbc nbn nca ncb ncc ncn nna nnb nnc nnn nnz nya nyc nyn nyy nzb nzz yaa yab yac yan yay yaz ybc yby ybz yca ycc ycy yna ynn yny yyb yyc yyy yyz yzb yzy zaa zab zac zan zay zaz zbb zbc zby znc znn zzy zzz