-er bbb bbe bbm bbo bbr be- beb bee bem beo ber bmb bme bmm bmo bmr bob boe bom boo bor brb bre brm bro brr ebb ebe ebm ebo ebr eeb eee eem eeo eer em- emb eme emm emo emr eo- eob eoe eom eoo eor erb ere erm ero err m-o m-r mbb mbe mbm mbo mbr meb mee mem meo mer mmb mme mmm mmo mmr mob moe mom moo mor mrb mre mrm mro mrr ob- obb obe obm obo obr oeb oee oem oeo oer om- omb ome omm omo omr oo- oob oom ooo oor or- orb ore orm oro orr rbb rbe rbm rbo rbr re- reb ree rem reo rer rmb rme rmm rmo rmr rob roe rom roo ror rrb rrm rrr