a-a a-b a-c aaa aab aac aag aah aak aao aar ab- aba abb abc abg abh abk abo abr ac- aca acb acc acg ach ack aco acr ag- aga agb agc agg agh agk ago agr aha ahb ahc ahg ahh ahk aho ahr aka akb akc akg akh akk ako akr aoa aob aoc aog aoh aok aoo aor ar- ara arb arc arg arh ark aro arr baa bab bac bag bah bak bao bar bba bbb bbc bbg bbh bbk bbo bbr bca bcb bcc bcg bch bck bco bcr bga bgb bgc bgg bgh bgk bgo bgr bha bhb bhc bhg bhh bhk bho bhr bka bkb bkc bkg bkk bko bkr boa bob boc bog boh bok boo bor bra brb brg brh brk bro brr c-- caa cab cac cag cah cak cao car cba cbb cbc cbg cbh cbk cbo cbr cca ccb ccc ccg cch cck cco ccr cga cgb cgc cgg cgh cgo cgr ch- cha chb chc chg chh chk cho chr cka ckb ckc ckh cko co- coa cob coc cog coh cok coo cor cra crb crc crg crh crk cro crr gaa gab gac gag gah gak gao gar gba gbc gbg gbh gbk gbo gbr gca gcb gcc gcg gch gck gco gcr gga ggb ggc ggg ggh ggo ggr gha ghb ghc ghg ghh gho ghr gka gkb gkh gko goa gob goc gog goh gok goo gor gra grb grc grg grh grk gro grr haa hab hac hag hah hak hao har hba hbb hbc hbg hbh hbk hbo hbr hca hcb hcc hcg hch hck hco hcr hga hgb hgc hgg hgh hgk hgo hgr hha hhb hhc hhg hhh hhk hho hhr hka hkb hkg hkh hkk hko hkr hoa hob hoc hog hoh hok hoo hor hr- hra hrb hrc hrg hrh hrk hro hrr ka- kaa kab kac kag kah kak kao kar kba kbb kbc kbh kbk kbo kbr kca kcb kcc kcg kch kck kcr kga kgb kgc kgh kgo kha khh khk kho khr kkb kkc kkh kkk kkr koa kob koc kog koh kok koo kor kra krc krg krk kro krr oaa oab oac oag oah oak oao oar ob- oba obb obc obg obh obk obo obr oc- oca ocb occ ocg och ock oco ocr oga ogc ogg ogh ogo oha ohc ohg ohh oho ohr oka okb okc okg okk oko okr oo- ooa oob ooc oog ooh ook ooo oor or- ora orb orc org orh ork oro orr ra- raa rab rac rag rah rak rao rar rba rbb rbc rbg rbh rbk rbo rbr rca rcb rcc rcg rch rco rcr rga rgb rgc rgg rgh rgk rgo rgr rh- rha rhb rhc rhg rhh rho rhr rkb rkc rkg rkk rko roa rob roc rog roh rok roo ror rra rrb rrc rrg rrh rrk rrr