-er bbb bbe bbi bbr bbt be- beb bee bei ber bet bez bi- bib bie bii bir bit biz brb bre bri brr brt brz btb bte bti btr btt btz bze bzr bzz ebb ebe ebi ebr ebt eeb eee eer eet eib eie eii eir eit erb ere eri err ert erz etb ete eti etr ett etz eze ezr ezz ibb ibe ibi ibr ibt ibz ie- iee iei ier iet iib iie iii iir iit ir- irb ire iri irr irt itb ite iti itt itz ize izi izz rbb rbe rbi rbr rbt re- reb ree rei rer ret rez rib rie rii rir rit riz rrb rri rrr rrt rtb rte rti rtr rtt rtz rzb rze tbb tbe tbi tbr tbt tbz te- teb tee tei ter tet tez tib tie tii tir tit tiz trb tre tri trr trt trz ttb tte tti ttr ttt tze zbb zbr zbt zeb zee zer zet zez zib zie zir zit ziz zte ztr zzr zzt zzz