-er bbb bbd bbe bbl bbr bbs bdb bdd bde bdl bdr bds be- beb bed bee bel ber bes blb bld ble bll blr bls brb brd bre brl brr brs bsb bsd bse bsl bsr bss dbb dbd dbe dbl dbr dbs ddb ddd dde ddl ddr dds de- deb ded dee del der des dl- dlb dld dle dll dlr dls drb drd dre drl drr drs dsb dsd dse dsl dsr dss ebb ebd ebe ebl ebr ebs ed- edb edd ede edl edr eds eeb eed eee eel eer ees elb eld ele ell elr els erb erd ere erl err ers es- esb esd ese esl esr ess lbb lbd lbe lbl lbr lbs ldb ldd lde ldl ldr lds leb led lee lel ler les llb lld lle lll llr lls lrb lrd lrr lrs lsb lsd lse lsl lsr lss rbb rbd rbe rbl rbr rbs rdb rdd rde rdl rdr rds re- reb red ree rel rer res rld rle rll rlr rls rrb rrd rrl rrr rrs rsb rsd rse rsl rsr rss sbb sbd sbe sbl sbr sbs sdb sdd sde sdl sdr sds se- seb sed see sel ser ses slb sld sle sll slr sls sr- srb srd sre srl srr srs ss- ssb ssd sse ssl ssr sss