a-a a-b a-c aaa aab aac aaf aah aak aao aar aau ab- aba abb abc abf abh abk abo abr abu ac- aca acb acc acf ach ack aco acr acu af- afa afb afc aff afh afk afo afr afu aha ahb ahc ahf ahh ahk aho ahr ahu aka akb akc akh akk ako akr aku aoa aob aoc aof aoh aok aoo aor aou ar- ara arb arc arf arh ark aro arr aru au- aua aub auc auf auh auk auo aur b-u baa bab bac baf bah bak bao bar bau bba bbb bbc bbf bbh bbk bbo bbr bbu bca bcb bcc bcf bch bck bco bcr bcu bfa bfb bfc bff bfh bfo bfr bfu bha bhb bhc bhf bhh bhk bho bhr bhu bka bkb bkc bkf bkk bko bkr boa bob boc bof boh bok boo bor bou bra brb brf brh brk bro brr bru bua bub buc buf buh buk buo bur buu c-- caa cab cac caf cah cak cao car cau cba cbb cbc cbf cbh cbk cbo cbr cbu cca ccb ccc ccf cch cck cco ccr ccu cfa cfb cfc cff cfh cfk cfo cfr cfu ch- cha chb chc chf chh chk cho chr chu cka ckb ckc ckh cko co- coa cob coc cof coh cok coo cor cou cra crb crc crf crh crk cro crr cru cua cub cuc cuf cuh cuk cuo cur cuu faa fab fac faf fah fak fao far fau fba fbb fbc fbf fbh fbk fbo fbr fbu fca fcb fcc fcf fck fco fcr fcu ffa ffc fff ffh ffk ffo ffr ffu fha fhb fhc fhf fhh fho fhr fka fkb fkc fkf fkk foa fob foc fof foh fok foo for fou fra frb frc frf frh frk fro frr fru fua fub fuf fuk fuo fur fuu haa hab hac haf hah hak hao har hau hba hbb hbc hbf hbh hbk hbo hbr hbu hca hcb hcc hcf hch hck hco hcr hfa hfb hfc hff hfh hfk hfo hfr hfu hha hhb hhc hhf hhh hhk hho hhr hhu hka hkb hkf hkh hkk hko hkr hku hoa hob hoc hof hoh hok hoo hor hou hr- hra hrb hrc hrf hrh hrk hro hrr hru hua hub huc huf huh huk huo hur huu ka- kaa kab kac kaf kah kak kao kar kau kba kbb kbc kbf kbh kbk kbo kbr kbu kca kcb kcc kch kck kcr kcu kfa kfc kff kfh kfo kfu kha khf khh khk kho khr khu kkb kkc kkh kkk kkr kku koa kob koc kof koh kok koo kor kou kra krc krf krk kro krr kru kub kuc kuh kuk kur kuu oaa oab oac oaf oah oak oao oar oau ob- oba obb obc obf obh obk obo obr obu oc- oca ocb occ ocf och ock oco ocr ocu of- ofa ofb ofc off ofo ofr ofu oha ohc ohf ohh oho ohr ohu oka okb okc okk oko okr oku oo- ooa oob ooc oof ooh ook ooo oor or- ora orb orc orf orh ork oro orr oru ou- oua ouc ouf ouh ouk ouo our ra- raa rab rac raf rah rak rao rar rau rba rbb rbc rbf rbh rbk rbo rbr rbu rca rcb rcc rcf rch rco rcr rcu rfa rfb rfc rff rfh rfk rfo rfr rfu rh- rha rhb rhc rhf rhh rho rhr rhu rkb rkc rkf rkk rko rku roa rob roc rof roh rok roo ror rou rra rrb rrc rrf rrh rrk rrr rru rua rub ruc ruf ruh ruk ruo rur ruu ua- uaa uab uac uaf uah uak uao uar uau uba ubb ubc ubf ubh ubk ubo ubr ubu uca ucb ucc ucf uch uck uco ucr ucu ufa ufc uff ufh ufo ufr ufu uha uhb uhc uhf uhh uho uhr uhu uka ukb ukc ukf ukk ukr uku uoa uob uoc uok uoo uor ur- ura urb urc urf urk uro urr uru uua uuc uur uuu