a-a a-b a-c aaa aab aac aaf aan aao aar aau ab- aba abb abc abf abn abo abr abu ac- aca acb acc acf acn aco acr acu af- afa afb afc aff afn afo afr afu an- ana anb anc anf ann ano anr anu aoa aob aoc aof aon aoo aor aou ar- ara arb arc arf arn aro arr aru au- aua aub auc auf aun auo aur b-u baa bab bac baf ban bao bar bau bba bbb bbc bbf bbn bbo bbr bbu bca bcb bcc bcf bcn bco bcr bcu bfa bfb bfc bff bfn bfo bfr bfu bna bnb bnc bnf bnn bno bnr bnu boa bob boc bof bon boo bor bou bra brb brf brn bro brr bru bua bub buc buf bun buo bur buu c-- caa cab cac caf can cao car cau cba cbb cbc cbf cbn cbo cbr cbu cca ccb ccc ccf ccn cco ccr ccu cfa cfb cfc cff cfn cfo cfr cfu cn- cna cnb cnc cnf cnn cno cnr cnu co- coa cob coc cof con coo cor cou cra crb crc crf crn cro crr cru cua cub cuc cuf cun cuo cur cuu faa fab fac faf fan fao far fau fba fbb fbc fbf fbn fbo fbr fbu fca fcb fcc fcf fcn fco fcr fcu ffa ffc fff ffn ffo ffr ffu fna fnb fnc fnf fnn fnr fnu foa fob foc fof fon foo for fou fra frb frc frf frn fro frr fru fua fub fuf fun fuo fur fuu naa nab nac naf nan nao nar nau nba nbb nbc nbf nbn nbo nbr nbu nca ncb ncc ncf ncn nco ncr ncu nfa nfb nfc nff nfn nfo nfr nfu nna nnb nnc nnf nnn nno nnu no- noa nob noc nof non noo nor nou nra nrb nrc nrf nrn nro nrr nru nua nub nuc nun nuo nur nuu oaa oab oac oaf oan oao oar oau ob- oba obb obc obf obn obo obr obu oc- oca ocb occ ocf ocn oco ocr ocu of- ofa ofb ofc off ofn ofo ofr ofu on- ona onb onc onf onn ono onr onu oo- ooa oob ooc oof oon ooo oor or- ora orb orc orf orn oro orr oru ou- oua ouc ouf oun ouo our ra- raa rab rac raf ran rao rar rau rba rbb rbc rbf rbn rbo rbr rbu rca rcb rcc rcf rcn rco rcr rcu rfa rfb rfc rff rfn rfo rfr rfu rna rnb rnc rnn rno rnr rnu roa rob roc rof ron roo ror rou rra rrb rrc rrf rrn rrr rru rua rub ruc ruf run ruo rur ruu ua- uaa uab uac uaf uan uao uar uau uba ubb ubc ubf ubn ubo ubr ubu uca ucb ucc ucf ucn uco ucr ucu ufa ufc uff ufn ufo ufr ufu un- una unb unc unf unn uno unr unu uoa uob uoc uon uoo uor ur- ura urb urc urf urn uro urr uru uua uuc uun uur uuu