c-- ccc cck ccm cco ccr ccs ckc ckm cko cks cmc cmk cmm cmo cmr cms co- coc cok com coo cor cos crc crk crm cro crr crs csc csk csm cso csr css kcc kck kcm kcr kcs kkc kkk kkm kkr kks kmc kmk kmm kmo kms koc kok kom koo kor kos krc krk kro krr krs ksc ksk ksm kso ksr kss m-o m-r mc- mcc mck mcm mco mcr mcs mkc mkk mkm mko mkr mks mmc mmk mmm mmo mmr mms moc mok mom moo mor mos mrc mrk mrm mro mrr mrs msc msk msm mso msr mss oc- occ ock ocm oco ocr ocs okc okk oko okr oks om- omc omm omo omr oms oo- ooc ook oom ooo oor oos or- orc ork orm oro orr ors os- osc osk osm oso osr oss rcc rcm rco rcr rcs rkc rkk rkm rko rks rmc rmm rmo rmr rms roc rok rom roo ror ros rrc rrk rrm rrr rrs rsc rsk rsm rso rsr rss scc sck scm sco scr scs sk- skc skk skm sko skr sks smc smk smm smo smr sms soc sok som soo sor sos sr- src srk srm sro srr srs ss- ssc ssk ssm sso ssr sss