a-a a-b a-c aaa aab aac aae aak aan aao aau ab- aba abb abc abe abk abn abo abu ac- aca acb acc ace ack acn aco acu aea aeb aec aee aek aen aeo aeu aka akb akc ake akk akn ako aku an- ana anb anc ane ank ann ano anu aoa aob aoc aoe aok aon aoo aou au- aua aub auc aue auk aun auo b-u baa bab bac bae bak ban bao bau bba bbb bbc bbe bbk bbn bbo bbu bca bcb bcc bce bck bcn bco bcu be- bea beb bec bee bek ben beo beu bka bkb bkc bke bkk bkn bko bna bnb bnc bne bnk bnn bno bnu boa bob boc boe bok bon boo bou bua bub buc bue buk bun buo buu c-- caa cab cac cae cak can cao cau cba cbb cbc cbe cbk cbn cbo cbu cca ccb ccc cce cck ccn cco ccu ce- cea ceb cec cee cek cen ceo ceu cka ckb ckc cko cn- cna cnb cnc cne cnn cno cnu co- coa cob coc coe cok con coo cou cua cub cuc cue cuk cun cuo cuu eaa eab eac eae eak ean eao eau eba ebb ebc ebe ebk ebn ebo ebu ec- eca ecb ecc ece eck ecn eco ecu eea eeb eec eee eek een eeo eka ekb ekc eke eko eku en- ena enb enc ene enk enn eno enu eo- eoa eob eoc eoe eok eon eoo eou eu- eua eub euc eue eun ka- kaa kab kac kae kak kan kao kau kba kbb kbc kbe kbk kbn kbo kbu kca kcb kcc kce kck kcn kcu ke- kea keb kec kee kek ken keo kkb kkc kke kkk kkn kku kn- kna knc kne knk knn kno knu koa kob koc koe kok kon koo kou kub kuc kue kuk kun kuu naa nab nac nae nak nan nao nau nba nbb nbc nbe nbk nbn nbo nbu nca ncb ncc nce nck ncn nco ncu ne- nea neb nec nee nek nen neo neu nka nkc nke nkk nkn nko nku nna nnb nnc nne nnk nnn nno nnu no- noa nob noc noe nok non noo nou nua nub nuc nue nuk nun nuo nuu oaa oab oac oae oak oan oao oau ob- oba obb obc obe obk obn obo obu oc- oca ocb occ ock ocn oco ocu oea oeb oec oee oen oeo oka okb okc oke okk oko oku on- ona onb onc one onk onn ono onu oo- ooa oob ooc ook oon ooo ou- oua ouc oue ouk oun ouo ua- uaa uab uac uae uak uan uao uau uba ubb ubc ube ubk ubn ubo ubu uca ucb ucc uce uck ucn uco ucu uea ueb uec uee uen uka ukb ukc uke ukk ukn uku un- una unb unc une unk unn uno unu uoa uob uoc uoe uok uon uoo uua uuc uue uun uuu