-er c-- ccc cce cck cco ccp ccr ce- cec cee cek ceo cep cer ckc cko co- coc coe cok coo cop cor cpc cpe cpk cpo cpp cpr crc cre crk cro crp crr ec- ecc ece eck eco ecr eec eee eek eeo eep eer ekc eke eko ekp ekr eo- eoc eoe eok eoo eop eor ep- epc epe epo epp epr erc ere erk ero erp err kcc kce kck kcp kcr ke- kec kee kek keo kep ker kkc kke kkk kkp kkr koc koe kok koo kop kor kpc kpe kpk kpo kpp kpr krc krk kro krp krr oc- occ ock oco ocp ocr oec oee oeo oep oer okc oke okk oko okp okr oo- ooc ook ooo oop oor op- opc ope opk opo opp opr or- orc ore ork oro orp orr p-p pcc pce pck pco pcp pcr pec pee pek peo pep per pkc pke pko pkp pkr poc poe pok poo pop por ppc ppe ppk ppo ppp ppr prc pre prk pro prp prr rcc rce rco rcp rcr re- rec ree rek reo rep rer rkc rke rkk rko rkp roc roe rok roo rop ror rpc rpe rpk rpo rpp rpr rrc rrk rrp rrr