-er c-- ccc cce ccf ccg cck cco ccr ce- cec cee cef ceg cek ceo cer cfc cfe cff cfg cfk cfo cfr cgc cge cgg cgo cgr ckc cko co- coc coe cof cog cok coo cor crc cre crf crg crk cro crr ec- ecc ece ecf ecg eck eco ecr eec eee eef eeg eek eeo eer ef- efc efe eff efg efo efr egc ege egf egg ego egr ekc eke ekf ekg eko ekr eo- eoc eoe eof eog eok eoo eor erc ere erf erg erk ero err fcc fce fcf fcg fck fco fcr fec fee fef feg fek feo fer ffc ffe fff ffg ffk ffo ffr fgc fge fgf fgg fgr fkc fkf fkg fkk foc foe fof fog fok foo for frc fre frf frg frk fro frr gcc gce gcf gcg gck gco gcr ge- gec gee gef geg gek geo ger gfc gfe gff gfk gfo gfr ggc ggg ggo ggr gko goc goe gof gog gok goo gor grc gre grf grg grk gro grr kcc kce kcg kck kcr ke- kec kee kef keg kek keo ker kfc kff kfg kfo kgc kgf kgo kkc kke kkk kkr koc koe kof kog kok koo kor krc krf krg krk kro krr oc- occ ocf ocg ock oco ocr oec oee oef oeg oeo oer of- ofc ofe off ofg ofo ofr ogc oge ogf ogg ogo okc oke okg okk oko okr oo- ooc oof oog ook ooo oor or- orc ore orf org ork oro orr rcc rce rcf rcg rco rcr re- rec ree ref reg rek reo rer rfc rfe rff rfg rfk rfo rfr rgc rge rgf rgg rgk rgo rgr rkc rke rkf rkg rkk rko roc roe rof rog rok roo ror rrc rrf rrg rrk rrr