a-a a-b a-c aaa aab aac aae aaf aak aan aau ab- aba abb abc abe abf abk abn abu ac- aca acb acc ace acf ack acn acu aea aeb aec aee aef aek aen aeu af- afa afb afc afe aff afk afn afu aka akb akc ake akk akn aku an- ana anb anc ane anf ank ann anu au- aua aub auc aue auf auk aun b-u baa bab bac bae baf bak ban bau bba bbb bbc bbe bbf bbk bbn bbu bca bcb bcc bce bcf bck bcn bcu be- bea beb bec bee bef bek ben beu bfa bfb bfc bfe bff bfn bfu bka bkb bkc bke bkf bkk bkn bna bnb bnc bne bnf bnk bnn bnu bua bub buc bue buf buk bun buu c-- caa cab cac cae caf cak can cau cba cbb cbc cbe cbf cbk cbn cbu cca ccb ccc cce ccf cck ccn ccu ce- cea ceb cec cee cef cek cen ceu cfa cfb cfc cfe cff cfk cfn cfu cka ckb ckc cn- cna cnb cnc cne cnf cnn cnu cua cub cuc cue cuf cuk cun cuu eaa eab eac eae eaf eak ean eau eba ebb ebc ebe ebf ebk ebn ebu ec- eca ecb ecc ece ecf eck ecn ecu eea eeb eec eee eef eek een ef- efa efb efc efe eff eka ekb ekc eke ekf eku en- ena enb enc ene enf enk enn enu eu- eua eub euc eue euf eun faa fab fac fae faf fak fan fau fba fbb fbc fbe fbf fbk fbn fbu fca fcb fcc fce fcf fck fcn fcu fea feb fec fee fef fek fen feu ffa ffc ffe fff ffk ffn ffu fka fkb fkc fkf fkk fna fnb fnc fne fnf fnk fnn fnu fua fub fue fuf fuk fun fuu ka- kaa kab kac kae kaf kak kan kau kba kbb kbc kbe kbf kbk kbn kbu kca kcb kcc kce kck kcn kcu ke- kea keb kec kee kef kek ken kfa kfc kff kfu kkb kkc kke kkk kkn kku kn- kna knc kne knf knk knn knu kub kuc kue kuk kun kuu naa nab nac nae naf nak nan nau nba nbb nbc nbe nbf nbk nbn nbu nca ncb ncc nce ncf nck ncn ncu ne- nea neb nec nee nef nek nen neu nfa nfb nfc nfe nff nfk nfn nfu nka nkc nke nkf nkk nkn nku nna nnb nnc nne nnf nnk nnn nnu nua nub nuc nue nuk nun nuu ua- uaa uab uac uae uaf uak uan uau uba ubb ubc ube ubf ubk ubn ubu uca ucb ucc uce ucf uck ucn ucu uea ueb uec uee uef uen ufa ufc ufe uff ufn ufu uka ukb ukc uke ukf ukk ukn uku un- una unb unc une unf unk unn unu uua uuc uue uun uuu