a-a a-b a-z aaa aab aam aao aaz ab- aba abb abm abo abz ama amb amm amo amz aoa aob aom aoo az- aza azb azm azo azz baa bab bam bao baz bba bbb bbm bbo bma bmb bmm bmo bmz boa bob bom boo boz bza bzo bzz m-o maa mab mam mao maz mba mbb mbm mbo mma mmb mmm mmo mmz moa mob mom moo moz mza mzb mzm oaa oab oam oao ob- oba obb obm obo om- oma omb omm omo omz oo- ooa oob oom ooo oza ozm ozo ozz zaa zab zam zao zaz zbb zbm zma zmb zmm zo- zoa zob zom zoo zzz