a-a a-b a-z aaa aab aak aao aav aaz ab- aba abb abk abo abv abz aka akb akk ako akv aoa aob aok aoo aov av- ava avb avk avo avz az- aza azb azo azz baa bab bak bao bav baz bba bbb bbk bbo bka bkb bkk bko bkv boa bob bok boo bov boz bva bvb bvk bvo bvv bza bzo bzz k-z ka- kaa kab kak kao kav kaz kba kbb kbk kbo kbz kkb kkk kkv koa kob kok koo koz kva kvb kvk kvo kvv kzo oaa oab oak oao oav ob- oba obb obk obo obv oka okb okk oko oo- ooa oob ook ooo oov ov- ova ovb ovo ovv oza ozo ozz v-a vaa vab vak vao vav vaz vba vbk vbo vbv vbz vka vkb voa vob vok voo vov voz vva vvb vvo vvv vvz zaa zab zak zao zav zaz zbb zbv zka zo- zoa zob zok zoo zzz