a-a a-b aaa aab aad aaf aan aao aar aau ab- aba abb abd abf abn abo abr abu ad- ada adb add adf adn ado adr adu af- afa afb afd aff afn afo afr afu an- ana anb and anf ann ano anr anu aoa aob aod aof aon aoo aor aou ar- ara arb ard arf arn aro arr aru au- aua aub aud auf aun auo aur b-u baa bab bad baf ban bao bar bau bba bbb bbd bbf bbn bbo bbr bbu bda bdb bdd bdf bdo bdr bdu bfa bfb bfd bff bfn bfo bfr bfu bna bnb bnd bnf bnn bno bnr bnu boa bob bod bof bon boo bor bou bra brb brd brf brn bro brr bru bua bub bud buf bun buo bur buu daa dab dad daf dan dao dar dau dba dbb dbd dbf dbn dbo dbr dbu dda ddb ddd ddf ddn ddo ddr ddu dfa dfb dfd dff dfn dfo dfr dfu dna dnb dnd dnf dnn dno dnr doa dob dod dof don doo dor dou dra drb drd drn dro drr dru dua dub dud duf dun duo dur faa fab fad faf fan fao far fau fba fbb fbd fbf fbn fbo fbr fbu fda fdb fdd fdf fdn fdo fdr fdu ffa ffd fff ffn ffo ffr ffu fna fnb fnd fnf fnn fnr fnu foa fob fof fon foo for fou fra frb frd frf frn fro frr fru fua fub fud fuf fun fuo fur fuu naa nab nad naf nan nao nar nau nba nbb nbd nbf nbn nbo nbr nbu nda ndb ndd ndf ndn ndo ndr ndu nfa nfb nfd nff nfn nfo nfr nfu nna nnb nnf nnn nno nnu no- noa nob nod nof non noo nor nou nra nrb nrd nrf nrn nro nrr nru nua nub nud nun nuo nur nuu oaa oab oad oaf oan oao oar oau ob- oba obb obd obf obn obo obr obu oda odb odd odf odn odo odr odu of- ofa ofb ofd off ofn ofo ofr ofu on- ona onb ond onf onn ono onr onu oo- ooa oob ood oof oon ooo oor or- ora orb ord orf orn oro orr oru ou- oua oud ouf oun ouo our ra- raa rab rad raf ran rao rar rau rba rbb rbd rbf rbn rbo rbr rbu rda rdb rdd rdf rdn rdo rdr rdu rfa rfb rfd rff rfn rfo rfr rfu rna rnb rnd rnn rno rnr rnu roa rob rod rof ron roo ror rou rra rrb rrd rrf rrn rrr rru rua rub rud ruf run ruo rur ruu ua- uaa uab uad uaf uan uao uar uau uba ubb ubf ubn ubo ubr ubu uda udb udd udf udn udo udr udu ufa ufd uff ufn ufo ufr ufu un- una unb und unf unn uno unr unu uoa uob uod uon uoo uor ur- ura urb urd urf urn uro urr uru uua uun uur uuu