-er bbb bbe bbi bbo bbr bbt be- beb bee bei beo ber bet bi- bib bie bii bio bir bit bob boe boi boo bor bot brb bre bri bro brr brt btb bte bti bto btr btt ebb ebe ebi ebo ebr ebt eeb eee eeo eer eet eib eie eii eio eir eit eo- eob eoe eoi eoo eor eot erb ere eri ero err ert etb ete eti eto etr ett ibb ibe ibi ibo ibr ibt ie- iee iei ier iet iib iie iii iio iir iit io- iob ioe ioi ioo ior iot ir- irb ire iri iro irr irt itb ite iti ito itt o-i ob- obb obe obi obo obr obt oeb oee oei oeo oer oet oib oie oii oio oir oit oo- oob ooi ooo oor oot or- orb ore ori oro orr ort ot- otb ote oti oto otr ott rbb rbe rbi rbo rbr rbt re- reb ree rei reo rer ret rib rie rii rio rir rit rob roe roi roo ror rot rrb rri rrr rrt rtb rte rti rto rtr rtt tbb tbe tbi tbo tbr tbt te- teb tee tei teo ter tet tib tie tii tio tir tit to- tob toe toi too tor tot trb tre tri tro trr trt ttb tte tti tto ttr ttt