c-- ccc cce ccf ccm cco ce- cec cee cef cem ceo cfc cfe cff cfm cfo cmc cme cmf cmm cmo co- coc coe cof com coo ec- ecc ece ecf ecm eco eec eee eef eem eeo ef- efc efe eff efm efo em- emc eme emf emm emo eo- eoc eoe eof eom eoo fcc fce fcf fcm fco fec fee fef fem feo ffc ffe fff ffm ffo fmc fme fmf fmm fmo foc foe fof fom foo m-f m-o mc- mcc mce mcf mcm mco mec mee mef mem meo mfc mfe mff mfm mfo mmc mme mmf mmm mmo moc moe mof mom moo oc- occ ocf ocm oco oec oee oef oem oeo of- ofc ofe off ofm ofo om- omc ome omf omm omo oo- ooc oof oom ooo