a-a a-b a-z aaa aab aao aav aay aaz ab- aba abb abo abv aby abz aoa aob aoo aov av- ava avb avo avy avz ay- aya ayo ayz az- aza azb azo azy azz baa bab bao bav bay baz bba bbb bbo bby boa bob boo bov boy boz bva bvb bvo bvv by- bya byo byz bza bzo bzz oaa oab oao oav ob- oba obb obo obv oby oo- ooa oob ooo oov ov- ova ovb ovo ovv oya oyo oza ozo ozz v-a vaa vab vao vav vay vaz vba vbo vbv vbz voa vob voo vov voy voz vva vvb vvo vvv vvz yaa yab yao yav yay yaz yby ybz yob yoo yoy yva yvo yvy yyb yyy yyz yzb yzy zaa zab zao zav zay zaz zbb zbv zby zo- zoa zob zoo zzy zzz