-er bbb bbe bbk bbm bbo bbr be- beb bee bek bem beo ber bkb bke bkk bkm bko bkr bmb bme bmk bmm bmo bmr bob boe bok bom boo bor brb bre brk brm bro brr ebb ebe ebk ebm ebo ebr eeb eee eek eem eeo eer ekb eke eko ekr em- emb eme emk emm emo emr eo- eob eoe eok eom eoo eor erb ere erk erm ero err kbb kbe kbk kbm kbo kbr ke- keb kee kek kem keo ker kkb kke kkk kkm kkr kmb kme kmk kmm kmo kob koe kok kom koo kor krk kro krr m-o m-r mbb mbe mbk mbm mbo mbr meb mee mek mem meo mer mkb mke mkk mkm mko mkr mmb mme mmk mmm mmo mmr mob moe mok mom moo mor mrb mre mrk mrm mro mrr ob- obb obe obk obm obo obr oeb oee oem oeo oer okb oke okk oko okr om- omb ome omm omo omr oo- oob ook oom ooo oor or- orb ore ork orm oro orr rbb rbe rbk rbm rbo rbr re- reb ree rek rem reo rer rkb rke rkk rkm rko rmb rme rmm rmo rmr rob roe rok rom roo ror rrb rrk rrm rrr