a-a a-b aaa aab aad aam aan ab- aba abb abd abm abn ad- ada adb add adm adn ama amb amd amm amn an- ana anb and anm ann baa bab bad bam ban bba bbb bbd bbm bbn bda bdb bdd bdm bma bmb bmd bmm bmn bna bnb bnd bnn daa dab dad dam dan dba dbb dbd dbm dbn dda ddb ddd ddm ddn dma dmb dmd dmm dmn dna dnb dnd dnm dnn maa mab mad mam man mba mbb mbd mbm mda mdb mdd mdm mdn mma mmb mmd mmm mmn mna mnb mnm mnn naa nab nad nam nan nba nbb nbd nbm nbn nda ndb ndd ndm ndn nma nmb nmd nmm nmn nna nnb nnm nnn