a-a a-b a-c aaa aab aac aak aam aao aap aar ab- aba abb abc abk abm abo abp abr ac- aca acb acc ack acm aco acp acr aka akb akc akk akm ako akp akr ama amb amc amk amm amo amp amr aoa aob aoc aok aom aoo aop aor ap- apa apb apc apk apm apo app apr ar- ara arb arc ark arm aro arp arr b-p baa bab bac bak bam bao bap bar bba bbb bbc bbk bbm bbo bbp bbr bca bcb bcc bck bcm bco bcp bcr bka bkb bkc bkk bkm bko bkp bkr bma bmb bmc bmk bmm bmo bmp bmr boa bob boc bok bom boo bop bor bpa bpb bpc bpm bpo bpp bpr bra brb brk brm bro brp brr c-- caa cab cac cak cam cao cap car cba cbb cbc cbk cbm cbo cbp cbr cca ccb ccc cck ccm cco ccp ccr cka ckb ckc ckm cko cma cmb cmc cmk cmm cmo cmp cmr co- coa cob coc cok com coo cop cor cpa cpb cpc cpk cpm cpo cpp cpr cra crb crc crk crm cro crp crr ka- kaa kab kac kak kam kao kap kar kba kbb kbc kbk kbm kbo kbp kbr kca kcb kcc kck kcm kcp kcr kkb kkc kkk kkm kkp kkr kma kmb kmc kmk kmm kmo kmp koa kob koc kok kom koo kop kor kpa kpc kpk kpm kpo kpp kpr kra krc krk kro krp krr m-o m-r maa mab mac mak mam mao map mar mba mbb mbc mbk mbm mbo mbp mbr mc- mca mcb mcc mck mcm mco mcp mcr mka mkb mkc mkk mkm mko mkp mkr mma mmb mmc mmk mmm mmo mmp mmr moa mob moc mok mom moo mop mor mpa mpb mpc mpk mpm mpo mpp mpr mra mrb mrc mrk mrm mro mrp mrr oaa oab oac oak oam oao oap oar ob- oba obb obc obk obm obo obp obr oc- oca ocb occ ock ocm oco ocp ocr oka okb okc okk oko okp okr om- oma omb omc omm omo omp omr oo- ooa oob ooc ook oom ooo oop oor op- opa opb opc opk opm opo opp opr or- ora orb orc ork orm oro orp orr p-p paa pab pac pak pam pao pap par pba pbb pbc pbk pbm pbo pbp pbr pca pcb pcc pck pcm pco pcp pcr pka pkb pkc pkm pko pkp pkr pma pmb pmc pmk pmm pmo pmp pmr poa pob poc pok pom poo pop por ppa ppb ppc ppk ppm ppo ppp ppr pra prb prc prk prm pro prp prr ra- raa rab rac rak ram rao rap rar rba rbb rbc rbk rbm rbo rbp rbr rca rcb rcc rcm rco rcp rcr rkb rkc rkk rkm rko rkp rma rmb rmc rmm rmo rmp rmr roa rob roc rok rom roo rop ror rpa rpb rpc rpk rpm rpo rpp rpr rra rrb rrc rrk rrm rrp rrr