c-- ccc ccf ccm cco cfc cff cfm cfo cmc cmf cmm cmo cmy co- coc cof com coo coy cyc cyf cym cyo fcc fcf fcm fco fcy ffc fff ffm ffo ffy fmc fmf fmm fmo foc fof fom foo foy fy- fyc fyo m-f m-o mc- mcc mcf mcm mco mfc mff mfm mfo mfy mmc mmf mmm mmo moc mof mom moo moy my- myc myf mym myo oc- occ ocf ocm oco of- ofc off ofm ofo om- omc omf omm omo omy oo- ooc oof oom ooo oyo ycc ycf yco ycy yfc yff yfm ymc ymm ymo yoc yof yom yoo yoy yyc yyf yyy