a-a a-c aaa aac aae aaf aam ac- aca acc ace acf acm aea aec aee aef aem af- afa afc afe aff afm ama amc ame amf amm c-- caa cac cae caf cam cca ccc cce ccf ccm ce- cea cec cee cef cem cfa cfc cfe cff cfm cma cmc cme cmf cmm eaa eac eae eaf eam ec- eca ecc ece ecf ecm eea eec eee eef eem ef- efa efc efe eff efm em- ema emc eme emf emm faa fac fae faf fam fca fcc fce fcf fcm fea fec fee fef fem ffa ffc ffe fff ffm fma fmc fme fmf fmm m-f maa mac mae maf mam mc- mca mcc mce mcf mcm mea mec mee mef mem mfa mfc mfe mff mfm mma mmc mme mmf mmm