c-- ccc cck ccm cco ccs ckc ckm cko cks cmc cmk cmm cmo cms co- coc cok com coo cos csc csk csm cso css kcc kck kcm kcs kkc kkk kkm kks kmc kmk kmm kmo kms koc kok kom koo kos ksc ksk ksm kso kss m-o mc- mcc mck mcm mco mcs mkc mkk mkm mko mks mmc mmk mmm mmo mms moc mok mom moo mos msc msk msm mso mss oc- occ ock ocm oco ocs okc okk oko oks om- omc omm omo oms oo- ooc ook oom ooo oos os- osc osk osm oso oss scc sck scm sco scs sk- skc skk skm sko sks smc smk smm smo sms soc sok som soo sos ss- ssc ssk ssm sso sss