c-- ccc cce ccm cco ccs ce- cec cee cem ceo ces cmc cme cmm cmo cms co- coc coe com coo cos csc cse csm cso css ec- ecc ece ecm eco ecs eec eee eem eeo ees em- emc eme emm emo ems eo- eoc eoe eom eoo eos es- esc ese esm eso ess m-o mc- mcc mce mcm mco mcs mec mee mem meo mes mmc mme mmm mmo mms moc moe mom moo mos msc mse msm mso mss oc- occ ocm oco ocs oec oee oem oeo oes om- omc ome omm omo oms oo- ooc oom ooo oos os- osc ose osm oso oss scc sce scm sco scs se- sec see sem seo ses smc sme smm smo sms soc soe som soo sos ss- ssc sse ssm sso sss