-er c-- ccc cce ccf cck ccm cco ccr ccs ce- cec cee cef cek cem ceo cer ces cfc cfe cff cfk cfm cfo cfr cfs ckc ckm cko cks cmc cme cmf cmk cmm cmo cmr cms co- coc coe cof cok com coo cor cos crc cre crf crk crm cro crr crs csc cse csf csk csm cso csr css ec- ecc ece ecf eck ecm eco ecr ecs eec eee eef eek eem eeo eer ees ef- efc efe eff efm efo efr efs ekc eke ekf eko ekr eks em- emc eme emf emk emm emo emr ems eo- eoc eoe eof eok eom eoo eor eos erc ere erf erk erm ero err ers es- esc ese esf esk esm eso esr ess fcc fce fcf fck fcm fco fcr fcs fec fee fef fek fem feo fer fes ffc ffe fff ffk ffm ffo ffr ffs fkc fkf fkk fkm fmc fme fmf fmm fmo fmr fms foc foe fof fok fom foo for fos frc fre frf frk frm fro frr frs fsc fse fsf fsk fsm fso fsr fss kcc kce kck kcm kcr kcs ke- kec kee kef kek kem keo ker kes kfc kff kfm kfo kfs kkc kke kkk kkm kkr kks kmc kme kmf kmk kmm kmo kms koc koe kof kok kom koo kor kos krc krf krk kro krr krs ksc kse ksf ksk ksm kso ksr kss m-f m-o m-r mc- mcc mce mcf mck mcm mco mcr mcs mec mee mef mek mem meo mer mes mfc mfe mff mfm mfo mfr mfs mkc mke mkk mkm mko mkr mks mmc mme mmf mmk mmm mmo mmr mms moc moe mof mok mom moo mor mos mrc mre mrf mrk mrm mro mrr mrs msc mse msf msk msm mso msr mss oc- occ ocf ock ocm oco ocr ocs oec oee oef oem oeo oer oes of- ofc ofe off ofm ofo ofr ofs okc oke okk oko okr oks om- omc ome omf omm omo omr oms oo- ooc oof ook oom ooo oor oos or- orc ore orf ork orm oro orr ors os- osc ose osf osk osm oso osr oss rcc rce rcf rcm rco rcr rcs re- rec ree ref rek rem reo rer res rfc rfe rff rfk rfm rfo rfr rfs rkc rke rkf rkk rkm rko rks rmc rme rmf rmm rmo rmr rms roc roe rof rok rom roo ror ros rrc rrf rrk rrm rrr rrs rsc rse rsf rsk rsm rso rsr rss scc sce scf sck scm sco scr scs se- sec see sef sek sem seo ser ses sfc sfe sff sfk sfm sfo sfr sfs sk- skc ske skf skk skm sko skr sks smc sme smf smk smm smo smr sms soc soe sof sok som soo sor sos sr- src sre srf srk srm sro srr srs ss- ssc sse ssf ssk ssm sso ssr sss