-er -up b-p b-u bbb bbe bbk bbp bbr bbu be- beb bee bek bep ber beu bkb bke bkk bkp bkr bpb bpe bpp bpr bpu brb bre brk brp brr bru bub bue buk bup bur buu ebb ebe ebk ebp ebr ebu eeb eee eek eep eer ekb eke ekp ekr eku ep- epb epe epp epr epu erb ere erk erp err eru eu- eub eue eup eur kbb kbe kbk kbp kbr kbu ke- keb kee kek kep ker kkb kke kkk kkp kkr kku kpe kpk kpp kpr kpu krk krp krr kru kub kue kuk kup kur kuu p-p pbb pbe pbk pbp pbr pbu peb pee pek pep per peu pkb pke pkp pkr pku ppb ppe ppk ppp ppr ppu prb pre prk prp prr pru pub pue puk pup pur puu rbb rbe rbk rbp rbr rbu re- reb ree rek rep rer reu rkb rke rkk rkp rku rpb rpe rpk rpp rpr rpu rrb rrk rrp rrr rru rub rue ruk rup rur ruu ubb ube ubk ubp ubr ubu ueb uee uep uer ukb uke ukk ukp ukr uku up- upb upe upk upp upr upu ur- urb ure urk urp urr uru uue uur uuu