-er b-u bbb bbe bbi bbo bbr bbu be- beb bee bei beo ber beu bi- bib bie bii bio bir biu bob boe boi boo bor bou brb bre bri bro brr bru bub bue bui buo bur buu ebb ebe ebi ebo ebr ebu eeb eee eeo eer eib eie eii eio eir eiu eo- eob eoe eoi eoo eor eou erb ere eri ero err eru eu- eub eue eui eur ibb ibe ibi ibo ibr ibu ie- iee iei ier iib iie iii iio iir iiu io- iob ioe ioi ioo ior iou ir- irb ire iri iro irr iru iu- iub iue iui iur o-i ob- obb obe obi obo obr obu oeb oee oei oeo oer oib oie oii oio oir oiu oo- oob ooi ooo oor or- orb ore ori oro orr oru ou- oue oui ouo our rbb rbe rbi rbo rbr rbu re- reb ree rei reo rer reu rib rie rii rio rir rob roe roi roo ror rou rrb rri rrr rru rub rue rui ruo rur ruu ubb ube ubi ubo ubr ubu ueb uee uei uer uib uie uii uio uir uiu uob uoe uoo uor ur- urb ure uri uro urr uru uue uur uuu