a-a a-b a-c aaa aab aac aak aam aan aao aar ab- aba abb abc abk abm abn abo abr ac- aca acb acc ack acm acn aco acr aka akb akc akk akm akn ako akr ama amb amc amk amm amn amo amr an- ana anb anc ank anm ann ano anr aoa aob aoc aok aom aon aoo aor ar- ara arb arc ark arm arn aro arr baa bab bac bak bam ban bao bar bba bbb bbc bbk bbm bbn bbo bbr bca bcb bcc bck bcm bcn bco bcr bka bkb bkc bkk bkm bkn bko bkr bma bmb bmc bmk bmm bmn bmo bmr bna bnb bnc bnk bnn bno bnr boa bob boc bok bom bon boo bor bra brb brk brm brn bro brr c-- caa cab cac cak cam can cao car cba cbb cbc cbk cbm cbn cbo cbr cca ccb ccc cck ccm ccn cco ccr cka ckb ckc ckm cko cma cmb cmc cmk cmm cmn cmo cmr cn- cna cnb cnc cnm cnn cno cnr co- coa cob coc cok com con coo cor cra crb crc crk crm crn cro crr ka- kaa kab kac kak kam kan kao kar kba kbb kbc kbk kbm kbn kbo kbr kca kcb kcc kck kcm kcn kcr kkb kkc kkk kkm kkn kkr kma kmb kmc kmk kmm kmo kn- kna knc knk knm knn kno knr koa kob koc kok kom kon koo kor kra krc krk krn kro krr m-o m-r maa mab mac mak mam man mao mar mba mbb mbc mbk mbm mbo mbr mc- mca mcb mcc mck mcm mcn mco mcr mka mkb mkc mkk mkm mkn mko mkr mma mmb mmc mmk mmm mmn mmo mmr mna mnb mnc mnk mnm mnn mno mnr moa mob moc mok mom mon moo mor mra mrb mrc mrk mrm mrn mro mrr naa nab nac nak nam nan nao nar nba nbb nbc nbk nbm nbn nbo nbr nca ncb ncc nck ncm ncn nco ncr nka nkc nkk nkm nkn nko nkr nma nmb nmc nmk nmm nmn nmo nmr nna nnb nnc nnk nnm nnn nno no- noa nob noc nok nom non noo nor nra nrb nrc nrk nrm nrn nro nrr oaa oab oac oak oam oan oao oar ob- oba obb obc obk obm obn obo obr oc- oca ocb occ ock ocm ocn oco ocr oka okb okc okk oko okr om- oma omb omc omm omn omo omr on- ona onb onc onk onn ono onr oo- ooa oob ooc ook oom oon ooo oor or- ora orb orc ork orm orn oro orr ra- raa rab rac rak ram ran rao rar rba rbb rbc rbk rbm rbn rbo rbr rca rcb rcc rcm rcn rco rcr rkb rkc rkk rkm rko rma rmb rmc rmm rmn rmo rmr rna rnb rnc rnm rnn rno rnr roa rob roc rok rom ron roo ror rra rrb rrc rrk rrm rrn rrr