-er c-- ccc cce ccm cco ccp ccr ccx ce- cec cee cem ceo cep cer cex cmc cme cmm cmo cmp cmr cmx co- coc coe com coo cop cor cox cpc cpe cpm cpo cpp cpr cpx crc cre crm cro crp crr crx cxc cxo cxp cxr cxx ec- ecc ece ecm eco ecr ecx eec eee eem eeo eep eer eex em- emc eme emm emo emp emr emx eo- eoc eoe eom eoo eop eor ep- epc epe epm epo epp epr epx erc ere erm ero erp err ex- exc exe exo exp exr exx m-o m-r mc- mcc mce mcm mco mcp mcr mcx mec mee mem meo mep mer mex mmc mme mmm mmo mmp mmr mmx moc moe mom moo mop mor mox mpc mpe mpm mpo mpp mpr mpx mrc mre mrm mro mrp mrr mrx mxc mxp mxr oc- occ ocm oco ocp ocr ocx oec oee oem oeo oep oer oex om- omc ome omm omo omp omr omx oo- ooc oom ooo oop oor oox op- opc ope opm opo opp opr opx or- orc ore orm oro orp orr orx ox- oxc oxo oxx p-p pcc pce pcm pco pcp pcr pcx pec pee pem peo pep per pex pmc pme pmm pmo pmp pmr pmx poc poe pom poo pop por pox ppc ppe ppm ppo ppp ppr ppx prc pre prm pro prp prr prx pxc pxe pxm pxr rcc rce rcm rco rcp rcr rcx re- rec ree rem reo rep rer rex rmc rme rmm rmo rmp rmr rmx roc roe rom roo rop ror rox rpc rpe rpm rpo rpp rpr rpx rrc rrm rrp rrr rxp rxr xcp xcr xcx xee xem xep xer xex xmc xmm xmo xmp xmr xmx xoc xom xoo xop xor xox xpc xpe xpm xpo xpp xrc xrx xxo xxp xxx