-er c-- ccc cce ccm cco ccr ce- cec cee cem ceo cer cmc cme cmm cmo cmr co- coc coe com coo cor crc cre crm cro crr ec- ecc ece ecm eco ecr eec eee eem eeo eer em- emc eme emm emo emr eo- eoc eoe eom eoo eor erc ere erm ero err m-o m-r mc- mcc mce mcm mco mcr mec mee mem meo mer mmc mme mmm mmo mmr moc moe mom moo mor mrc mre mrm mro mrr oc- occ ocm oco ocr oec oee oem oeo oer om- omc ome omm omo omr oo- ooc oom ooo oor or- orc ore orm oro orr rcc rce rcm rco rcr re- rec ree rem reo rer rmc rme rmm rmo rmr roc roe rom roo ror rrc rrm rrr