c-- ccc cce ccm cco cct ce- cec cee cem ceo cet cmc cme cmm cmo cmt co- coc coe com coo cot ctc cte ctm cto ctt ec- ecc ece ecm eco ect eec eee eem eeo eet em- emc eme emm emo emt eo- eoc eoe eom eoo eot etc ete etm eto ett m-o mc- mcc mce mcm mco mct mec mee mem meo met mmc mme mmm mmo mmt moc moe mom moo mot mtc mte mtm mto mtt oc- occ ocm oco oct oec oee oem oeo oet om- omc ome omm omo omt oo- ooc oom ooo oot ot- otc ote otm oto ott tcc tce tcm tco tct te- tec tee tem teo tet tmc tme tmm tmo tmt to- toc toe tom too tot ttc tte ttm tto ttt