-er c-- ccc cce cck ccm cco ccr ce- cec cee cek cem ceo cer ckc ckm cko cmc cme cmk cmm cmo cmr co- coc coe cok com coo cor crc cre crk crm cro crr ec- ecc ece eck ecm eco ecr eec eee eek eem eeo eer ekc eke eko ekr em- emc eme emk emm emo emr eo- eoc eoe eok eom eoo eor erc ere erk erm ero err kcc kce kck kcm kcr ke- kec kee kek kem keo ker kkc kke kkk kkm kkr kmc kme kmk kmm kmo koc koe kok kom koo kor krc krk kro krr m-o m-r mc- mcc mce mck mcm mco mcr mec mee mek mem meo mer mkc mke mkk mkm mko mkr mmc mme mmk mmm mmo mmr moc moe mok mom moo mor mrc mre mrk mrm mro mrr oc- occ ock ocm oco ocr oec oee oem oeo oer okc oke okk oko okr om- omc ome omm omo omr oo- ooc ook oom ooo oor or- orc ore ork orm oro orr rcc rce rcm rco rcr re- rec ree rek rem reo rer rkc rke rkk rkm rko rmc rme rmm rmo rmr roc roe rok rom roo ror rrc rrk rrm rrr