a-a a-b a-z aaa aab aan aau aaz ab- aba abb abn abu abz an- ana anb ann anu anz au- aua aub aun auz az- aza azb azn azu azz b-u baa bab ban bau baz bba bbb bbn bbu bna bnb bnn bnu bnz bua bub bun buu buz bza bzn bzu bzz naa nab nan nau naz nba nbb nbn nbu nna nnb nnn nnu nnz nua nub nun nuu nzb nzz ua- uaa uab uan uau uaz uba ubb ubn ubu un- una unb unn unu uua uun uuu uza uzb uzu zaa zab zan zaz zbb znn zub zun zuz zzz