-er b-u bbb bbe bbi bbk bbo bbr bbu be- beb bee bei bek beo ber beu bi- bib bie bii bik bio bir biu bkb bke bkk bko bkr bob boe boi bok boo bor bou brb bre bri brk bro brr bru bub bue bui buk buo bur buu ebb ebe ebi ebk ebo ebr ebu eeb eee eek eeo eer eib eie eii eik eio eir eiu ekb eke eki eko ekr eku eo- eob eoe eoi eok eoo eor eou erb ere eri erk ero err eru eu- eub eue eui eur ibb ibe ibi ibk ibo ibr ibu ie- iee iei iek ier iib iie iii iio iir iiu ikb ike iki ikk iko ikr iku io- iob ioe ioi ioo ior iou ir- irb ire iri irk iro irr iru iu- iub iue iui iur kbb kbe kbi kbk kbo kbr kbu ke- keb kee kei kek keo ker kib kie kii kik kio kir kiu kkb kke kki kkk kkr kku kob koe koi kok koo kor kou kri krk kro krr kru kub kue kui kuk kur kuu o-i ob- obb obe obi obk obo obr obu oeb oee oei oeo oer oib oie oii oik oio oir oiu okb oke oki okk oko okr oku oo- oob ooi ook ooo oor or- orb ore ori ork oro orr oru ou- oue oui ouk ouo our rbb rbe rbi rbk rbo rbr rbu re- reb ree rei rek reo rer reu rib rie rii rik rio rir rkb rke rkk rko rku rob roe roi rok roo ror rou rrb rri rrk rrr rru rub rue rui ruk ruo rur ruu ubb ube ubi ubk ubo ubr ubu ueb uee uei uer uib uie uii uio uir uiu ukb uke uki ukk ukr uku uob uoe uok uoo uor ur- urb ure uri urk uro urr uru uue uur uuu