-er bbb bbe bbl bbr bbs bbt be- beb bee bel ber bes bet blb ble bll blr bls blt brb bre brl brr brs brt bsb bse bsl bsr bss bst btb bte btl btr bts btt ebb ebe ebl ebr ebs ebt eeb eee eel eer ees eet elb ele ell elr els elt erb ere erl err ers ert es- esb ese esl esr ess est etb ete etl etr ets ett lbb lbe lbl lbr lbs lbt leb lee lel ler les let llb lle lll llr lls llt lrb lrr lrs lrt lsb lse lsl lsr lss lst ltb lte ltl ltr lts ltt rbb rbe rbl rbr rbs rbt re- reb ree rel rer res ret rle rll rlr rls rlt rrb rrl rrr rrs rrt rsb rse rsl rsr rss rst rtb rte rtl rtr rts rtt sbb sbe sbl sbr sbs sbt se- seb see sel ser ses set slb sle sll slr sls slt sr- srb sre srl srr srs srt ss- ssb sse ssl ssr sss sst stb ste stl str sts stt tbb tbe tbl tbr tbs tbt te- teb tee tel ter tes tet tle tll tlr tls tlt trb tre trl trr trs trt tsb tse tsl tsr tss tst ttb tte ttl ttr tts ttt