-er c-- ccc cce ccf cco ccp ccr ce- cec cee cef ceo cep cer cfc cfe cff cfo cfp cfr co- coc coe cof coo cop cor cpc cpe cpf cpo cpp cpr crc cre crf cro crp crr ec- ecc ece ecf eco ecr eec eee eef eeo eep eer ef- efc efe eff efo efp efr eo- eoc eoe eof eoo eop eor ep- epc epe epf epo epp epr erc ere erf ero erp err fcc fce fcf fco fcp fcr fec fee fef feo fep fer ffc ffe fff ffo ffp ffr foc foe fof foo fop for fpc fpe fpo fpp fpr frc fre frf fro frp frr oc- occ ocf oco ocp ocr oec oee oef oeo oep oer of- ofc ofe off ofo ofp ofr oo- ooc oof ooo oop oor op- opc ope opf opo opp opr or- orc ore orf oro orp orr p-p pcc pce pcf pco pcp pcr pec pee pef peo pep per pfc pfe pff pfo pfp pfr poc poe pof poo pop por ppc ppe ppf ppo ppp ppr prc pre prf pro prp prr rcc rce rcf rco rcp rcr re- rec ree ref reo rep rer rfc rfe rff rfo rfp rfr roc roe rof roo rop ror rpc rpe rpf rpo rpp rpr rrc rrf rrp rrr