-er b-u bbb bbe bbk bbm bbr bbu be- beb bee bek bem ber beu bkb bke bkk bkm bkr bmb bme bmk bmm bmr bmu brb bre brk brm brr bru bub bue buk bum bur buu ebb ebe ebk ebm ebr ebu eeb eee eek eem eer ekb eke ekr eku em- emb eme emk emm emr emu erb ere erk erm err eru eu- eub eue eur kbb kbe kbk kbm kbr kbu ke- keb kee kek kem ker kkb kke kkk kkm kkr kku kmb kme kmk kmm kmu krk krr kru kub kue kuk kum kur kuu m-r mbb mbe mbk mbm mbr mbu meb mee mek mem mer meu mkb mke mkk mkm mkr mku mmb mme mmk mmm mmr mmu mrb mre mrk mrm mrr mru mub mue muk mum mur muu rbb rbe rbk rbm rbr rbu re- reb ree rek rem rer reu rkb rke rkk rkm rku rmb rme rmm rmr rrb rrk rrm rrr rru rub rue ruk rum rur ruu ubb ube ubk ubr ubu ueb uee uem uer ukb uke ukk ukr uku um- umb ume umm umr umu ur- urb ure urk urm urr uru uue uum uur uuu