-er c-- ccc cce cck ccm cco ccr ccs ce- cec cee cek cem ceo cer ces ckc ckm cko cks cmc cme cmk cmm cmo cmr cms co- coc coe cok com coo cor cos crc cre crk crm cro crr crs csc cse csk csm cso csr css ec- ecc ece eck ecm eco ecr ecs eec eee eek eem eeo eer ees ekc eke eko ekr eks em- emc eme emk emm emo emr ems eo- eoc eoe eok eom eoo eor eos erc ere erk erm ero err ers es- esc ese esk esm eso esr ess kcc kce kck kcm kcr kcs ke- kec kee kek kem keo ker kes kkc kke kkk kkm kkr kks kmc kme kmk kmm kmo kms koc koe kok kom koo kor kos krc krk kro krr krs ksc kse ksk ksm kso ksr kss m-o m-r mc- mcc mce mck mcm mco mcr mcs mec mee mek mem meo mer mes mkc mke mkk mkm mko mkr mks mmc mme mmk mmm mmo mmr mms moc moe mok mom moo mor mos mrc mre mrk mrm mro mrr mrs msc mse msk msm mso msr mss oc- occ ock ocm oco ocr ocs oec oee oem oeo oer oes okc oke okk oko okr oks om- omc ome omm omo omr oms oo- ooc ook oom ooo oor oos or- orc ore ork orm oro orr ors os- osc ose osk osm oso osr oss rcc rce rcm rco rcr rcs re- rec ree rek rem reo rer res rkc rke rkk rkm rko rks rmc rme rmm rmo rmr rms roc roe rok rom roo ror ros rrc rrk rrm rrr rrs rsc rse rsk rsm rso rsr rss scc sce sck scm sco scr scs se- sec see sek sem seo ser ses sk- skc ske skk skm sko skr sks smc sme smk smm smo smr sms soc soe sok som soo sor sos sr- src sre srk srm sro srr srs ss- ssc sse ssk ssm sso ssr sss