a-a a-b a-c aaa aab aac aae aaf aam aao ab- aba abb abc abe abf abm abo ac- aca acb acc ace acf acm aco aea aeb aec aee aef aem aeo af- afa afb afc afe aff afm afo ama amb amc ame amf amm amo aoa aob aoc aoe aof aom aoo baa bab bac bae baf bam bao bba bbb bbc bbe bbf bbm bbo bca bcb bcc bce bcf bcm bco be- bea beb bec bee bef bem beo bfa bfb bfc bfe bff bfm bfo bma bmb bmc bme bmf bmm bmo boa bob boc boe bof bom boo c-- caa cab cac cae caf cam cao cba cbb cbc cbe cbf cbm cbo cca ccb ccc cce ccf ccm cco ce- cea ceb cec cee cef cem ceo cfa cfb cfc cfe cff cfm cfo cma cmb cmc cme cmf cmm cmo co- coa cob coc coe cof com coo eaa eab eac eae eaf eam eao eba ebb ebc ebe ebf ebm ebo ec- eca ecb ecc ece ecf ecm eco eea eeb eec eee eef eem eeo ef- efa efb efc efe eff efm efo em- ema emb emc eme emf emm emo eo- eoa eob eoc eoe eof eom eoo faa fab fac fae faf fam fao fba fbb fbc fbe fbf fbm fbo fca fcb fcc fce fcf fcm fco fea feb fec fee fef fem feo ffa ffc ffe fff ffm ffo fma fmb fmc fme fmf fmm fmo foa fob foc foe fof fom foo m-f m-o maa mab mac mae maf mam mao mba mbb mbc mbe mbf mbm mbo mc- mca mcb mcc mce mcf mcm mco mea meb mec mee mef mem meo mfa mfb mfc mfe mff mfm mfo mma mmb mmc mme mmf mmm mmo moa mob moc moe mof mom moo oaa oab oac oae oaf oam oao ob- oba obb obc obe obf obm obo oc- oca ocb occ ocf ocm oco oea oeb oec oee oef oem oeo of- ofa ofb ofc ofe off ofm ofo om- oma omb omc ome omf omm omo oo- ooa oob ooc oof oom ooo