c-- ccc ccm cco ccr ccs cmc cmm cmo cmr cms co- coc com coo cor cos crc crm cro crr crs csc csm cso csr css m-o m-r mc- mcc mcm mco mcr mcs mmc mmm mmo mmr mms moc mom moo mor mos mrc mrm mro mrr mrs msc msm mso msr mss oc- occ ocm oco ocr ocs om- omc omm omo omr oms oo- ooc oom ooo oor oos or- orc orm oro orr ors os- osc osm oso osr oss rcc rcm rco rcr rcs rmc rmm rmo rmr rms roc rom roo ror ros rrc rrm rrr rrs rsc rsm rso rsr rss scc scm sco scr scs smc smm smo smr sms soc som soo sor sos sr- src srm sro srr srs ss- ssc ssm sso ssr sss