a-a a-b aaa aab aad aaf aan aau ab- aba abb abd abf abn abu ad- ada adb add adf adn adu af- afa afb afd aff afn afu an- ana anb and anf ann anu au- aua aub aud auf aun b-u baa bab bad baf ban bau bba bbb bbd bbf bbn bbu bda bdb bdd bdf bdu bfa bfb bfd bff bfn bfu bna bnb bnd bnf bnn bnu bua bub bud buf bun buu daa dab dad daf dan dau dba dbb dbd dbf dbn dbu dda ddb ddd ddf ddn ddu dfa dfb dfd dff dfn dfu dna dnb dnd dnf dnn dua dub dud duf dun faa fab fad faf fan fau fba fbb fbd fbf fbn fbu fda fdb fdd fdf fdn fdu ffa ffd fff ffn ffu fna fnb fnd fnf fnn fnu fua fub fud fuf fun fuu naa nab nad naf nan nau nba nbb nbd nbf nbn nbu nda ndb ndd ndf ndn ndu nfa nfb nfd nff nfn nfu nna nnb nnf nnn nnu nua nub nud nun nuu ua- uaa uab uad uaf uan uau uba ubb ubf ubn ubu uda udb udd udf udn udu ufa ufd uff ufn ufu un- una unb und unf unn unu uua uun uuu