a-a a-b a-z aaa aab aad aan aaz ab- aba abb abd abn abz ad- ada adb add adn adz an- ana anb and ann anz az- aza azb azd azn azz baa bab bad ban baz bba bbb bbd bbn bda bdb bdd bdz bna bnb bnd bnn bnz bza bzd bzn bzz daa dab dad dan daz dba dbb dbd dbn dbz dda ddb ddd ddn ddz dna dnb dnd dnn dnz dza dzb dzd naa nab nad nan naz nba nbb nbd nbn nda ndb ndd ndn nna nnb nnn nnz nzb nzd nzz zaa zab zad zan zaz zbb znd znn zzz