a-a a-c aaa aac aaf aam aao ac- aca acc acf acm aco af- afa afc aff afm afo ama amc amf amm amo aoa aoc aof aom aoo c-- caa cac caf cam cao cca ccc ccf ccm cco cfa cfc cff cfm cfo cma cmc cmf cmm cmo co- coa coc cof com coo faa fac faf fam fao fca fcc fcf fcm fco ffa ffc fff ffm ffo fma fmc fmf fmm fmo foa foc fof fom foo m-f m-o maa mac maf mam mao mc- mca mcc mcf mcm mco mfa mfc mff mfm mfo mma mmc mmf mmm mmo moa moc mof mom moo oaa oac oaf oam oao oc- oca occ ocf ocm oco of- ofa ofc off ofm ofo om- oma omc omf omm omo oo- ooa ooc oof oom ooo