a-a a-b aaa aab aae aam aao ab- aba abb abe abm abo aea aeb aee aem aeo ama amb ame amm amo aoa aob aoe aom aoo baa bab bae bam bao bba bbb bbe bbm bbo be- bea beb bee bem beo bma bmb bme bmm bmo boa bob boe bom boo eaa eab eae eam eao eba ebb ebe ebm ebo eea eeb eee eem eeo em- ema emb eme emm emo eo- eoa eob eoe eom eoo m-o maa mab mae mam mao mba mbb mbe mbm mbo mea meb mee mem meo mma mmb mme mmm mmo moa mob moe mom moo oaa oab oae oam oao ob- oba obb obe obm obo oea oeb oee oem oeo om- oma omb ome omm omo oo- ooa oob oom ooo