-er c-- ccc cce ccf cck cco ccr ccv ce- cec cee cef cek ceo cer cev cfc cfe cff cfk cfo cfr cfv ckc cko co- coc coe cof cok coo cor cov crc cre crf crk cro crr crv cvc cve cvf cvk cvo cvr cvv ec- ecc ece ecf eck eco ecr ecv eec eee eef eek eeo eer eev ef- efc efe eff efo efr ekc eke ekf eko ekr ekv eo- eoc eoe eof eok eoo eor erc ere erf erk ero err erv evc eve evf evo evr evv fcc fce fcf fck fco fcr fcv fec fee fef fek feo fer fev ffc ffe fff ffk ffo ffr ffv fkc fkf fkk foc foe fof fok foo for frc fre frf frk fro frr fvc fvk kcc kce kck kcr ke- kec kee kef kek keo ker kev kfc kff kfo kkc kke kkk kkr kkv koc koe kof kok koo kor krc krf krk kro krr krv kvk kvo kvr kvv oc- occ ocf ock oco ocr ocv oec oee oef oeo oer of- ofc ofe off ofo ofr ofv okc oke okk oko okr oo- ooc oof ook ooo oor oov or- orc ore orf ork oro orr orv ov- ovc ove ovf ovo ovv rcc rce rcf rco rcr rcv re- rec ree ref rek reo rer rev rfc rfe rff rfk rfo rfr rfv rkc rke rkf rkk rko rkv roc roe rof rok roo ror rov rrc rrf rrk rrr rvc rve rvf rvo rvr rvv v-e vcc vce vcf vco vcr vec vee vef vek veo ver vfc vff vfr vfv voc voe vof vok voo vor vov vrc vre vrf vrk vrr vvc vvo vvr vvv