-er b-p bbb bbe bbk bbp bbr be- beb bee bek bep ber bkb bke bkk bkp bkr bpb bpe bpp bpr brb bre brk brp brr ebb ebe ebk ebp ebr eeb eee eek eep eer ekb eke ekp ekr ep- epb epe epp epr erb ere erk erp err kbb kbe kbk kbp kbr ke- keb kee kek kep ker kkb kke kkk kkp kkr kpe kpk kpp kpr krk krp krr p-p pbb pbe pbk pbp pbr peb pee pek pep per pkb pke pkp pkr ppb ppe ppk ppp ppr prb pre prk prp prr rbb rbe rbk rbp rbr re- reb ree rek rep rer rkb rke rkk rkp rpb rpe rpk rpp rpr rrb rrk rrp rrr