-er bbb bbe bbi bbr bbt be- beb bee bei ber bet bi- bib bie bii bir bit brb bre bri brr brt btb bte bti btr btt ebb ebe ebi ebr ebt eeb eee eer eet eib eie eii eir eit erb ere eri err ert etb ete eti etr ett ibb ibe ibi ibr ibt ie- iee iei ier iet iib iie iii iir iit ir- irb ire iri irr irt itb ite iti itt rbb rbe rbi rbr rbt re- reb ree rei rer ret rib rie rii rir rit rrb rri rrr rrt rtb rte rti rtr rtt tbb tbe tbi tbr tbt te- teb tee tei ter tet tib tie tii tir tit trb tre tri trr trt ttb tte tti ttr ttt