-er -ol bbb bbe bbk bbl bbo bbr bbt be- beb bee bek bel beo ber bet bkb bke bkk bkl bko bkr bkt blb ble blk bll blo blr blt bob boe bok bol boo bor bot brb bre brk brl bro brr brt btb bte btk btl bto btr btt ebb ebe ebk ebl ebo ebr ebt eeb eee eek eel eeo eer eet ekb eke ekl eko ekr ekt elb ele elk ell elo elr elt eo- eob eoe eok eol eoo eor eot erb ere erk erl ero err ert etb ete etk etl eto etr ett k-t kbb kbe kbk kbl kbo kbr ke- keb kee kek kel keo ker ket kkb kke kkk kkl kkr kkt kl- klb klo klr klt kob koe kok kol koo kor kot krk krl kro krr krt ktb kte ktk ktl kto ktr ktt lbb lbe lbk lbl lbo lbr lbt leb lee lek lel leo ler let lkb lkl lkr lkt llb lle llk lll llo llr llt lob loe lok lol loo lor lot lrb lrk lro lrr lrt ltb lte ltk ltl lto ltr ltt ob- obb obe obk obl obo obr obt oeb oee oel oeo oer oet okb oke okk okl oko okr olb ole olk oll olo olt oo- oob ook ool ooo oor oot or- orb ore ork orl oro orr ort ot- otb ote otk otl oto otr ott rbb rbe rbk rbl rbo rbr rbt re- reb ree rek rel reo rer ret rkb rke rkk rko rkt rle rll rlo rlr rlt rob roe rok rol roo ror rot rrb rrk rrl rrr rrt rtb rte rtk rtl rto rtr rtt tbb tbe tbk tbl tbo tbr tbt te- teb tee tek tel teo ter tet tkb tke tkk tkl tko tkr tkt tle tlk tll tlo tlr tlt to- tob toe tok tol too tor tot trb tre trk trl tro trr trt ttb tte ttk ttl tto ttr ttt