a-a a-b a-z aaa aab aas aay aaz ab- aba abb abs aby abz as- asa asb ass asy asz ay- aya ays ayz az- aza azb azs azy azz baa bab bas bay baz bba bbb bbs bby bsa bsb bss bsy by- bya bys byz bza bzs bzz saa sab sas say saz sba sbb sbs sby ss- ssa ssb sss ssz sy- sya syb sys sza yaa yab yas yay yaz ybs yby ybz ysa ysb yss ysy ysz yyb yys yyy yyz yzb yzy zaa zab zas zay zaz zbb zbs zby zsa zsz zzs zzy zzz