-er a-a a-c aaa aac aae aak aao aap aar ac- aca acc ace ack aco acp acr aea aec aee aek aeo aep aer aka akc ake akk ako akp akr aoa aoc aoe aok aoo aop aor ap- apa apc ape apk apo app apr ar- ara arc are ark aro arp arr c-- caa cac cae cak cao cap car cca ccc cce cck cco ccp ccr ce- cea cec cee cek ceo cep cer cka ckc cko co- coa coc coe cok coo cop cor cpa cpc cpe cpk cpo cpp cpr cra crc cre crk cro crp crr eaa eac eae eak eao eap ear ec- eca ecc ece eck eco ecr eea eec eee eek eeo eep eer eka ekc eke eko ekp ekr eo- eoa eoc eoe eok eoo eop eor ep- epa epc epe epo epp epr era erc ere erk ero erp err ka- kaa kac kae kak kao kap kar kca kcc kce kck kcp kcr ke- kea kec kee kek keo kep ker kkc kke kkk kkp kkr koa koc koe kok koo kop kor kpa kpc kpe kpk kpo kpp kpr kra krc krk kro krp krr oaa oac oae oak oao oap oar oc- oca occ ock oco ocp ocr oea oec oee oeo oep oer oka okc oke okk oko okp okr oo- ooa ooc ook ooo oop oor op- opa opc ope opk opo opp opr or- ora orc ore ork oro orp orr p-p paa pac pae pak pao pap par pca pcc pce pck pco pcp pcr pea pec pee pek peo pep per pka pkc pke pko pkp pkr poa poc poe pok poo pop por ppa ppc ppe ppk ppo ppp ppr pra prc pre prk pro prp prr ra- raa rac rae rak rao rap rar rca rcc rce rco rcp rcr re- rea rec ree rek reo rep rer rkc rke rkk rko rkp roa roc roe rok roo rop ror rpa rpc rpe rpk rpo rpp rpr rra rrc rrk rrp rrr