a-a a-b a-z aaa aab aam aar aaz ab- aba abb abm abr abz ama amb amm amr amz ar- ara arb arm arr arz az- aza azb azm azz baa bab bam bar baz bba bbb bbm bbr bma bmb bmm bmr bmz bra brb brm brr brz bza bzr bzz m-r maa mab mam mar maz mba mbb mbm mbr mma mmb mmm mmr mmz mra mrb mrm mrr mrz mza mzb mzm ra- raa rab ram rar raz rba rbb rbm rbr rma rmb rmm rmr rra rrb rrm rrr rza rzb rzm zaa zab zam zar zaz zbb zbm zbr zma zmb zmm zzr zzz