-er bbb bbe bbi bbk bbr be- beb bee bei bek ber bi- bib bie bii bik bir bkb bke bkk bkr brb bre bri brk brr ebb ebe ebi ebk ebr eeb eee eek eer eib eie eii eik eir ekb eke eki ekr erb ere eri erk err ibb ibe ibi ibk ibr ie- iee iei iek ier iib iie iii iir ikb ike iki ikk ikr ir- irb ire iri irk irr kbb kbe kbi kbk kbr ke- keb kee kei kek ker kib kie kii kik kir kkb kke kki kkk kkr kri krk krr rbb rbe rbi rbk rbr re- reb ree rei rek rer rib rie rii rik rir rkb rke rkk rrb rri rrk rrr