-er -ol bbb bbe bbk bbl bbo bbr bbs bbt be- beb bee bek bel beo ber bes bet bkb bke bkk bkl bko bkr bks bkt blb ble blk bll blo blr bls blt bob boe bok bol boo bor bos bot brb bre brk brl bro brr brs brt bsb bse bsk bsl bso bsr bss bst btb bte btk btl bto btr bts btt ebb ebe ebk ebl ebo ebr ebs ebt eeb eee eek eel eeo eer ees eet ekb eke ekl eko ekr eks ekt elb ele elk ell elo elr els elt eo- eob eoe eok eol eoo eor eos eot erb ere erk erl ero err ers ert es- esb ese esk esl eso esr ess est etb ete etk etl eto etr ets ett k-t kbb kbe kbk kbl kbo kbr kbs ke- keb kee kek kel keo ker kes ket kkb kke kkk kkl kkr kks kkt kl- klb klo klr kls klt kob koe kok kol koo kor kos kot krk krl kro krr krs krt ksb kse ksk ksl kso ksr kss kst ktb kte ktk ktl kto ktr kts ktt lbb lbe lbk lbl lbo lbr lbs lbt leb lee lek lel leo ler les let lkb lkl lkr lks lkt llb lle llk lll llo llr lls llt lob loe lok lol loo lor los lot lrb lrk lro lrr lrs lrt lsb lse lsk lsl lso lsr lss lst ltb lte ltk ltl lto ltr lts ltt ob- obb obe obk obl obo obr obs obt oeb oee oel oeo oer oes oet okb oke okk okl oko okr oks olb ole olk oll olo ols olt oo- oob ook ool ooo oor oos oot or- orb ore ork orl oro orr ors ort os- osb ose osk osl oso osr oss ost ot- otb ote otk otl oto otr ots ott rbb rbe rbk rbl rbo rbr rbs rbt re- reb ree rek rel reo rer res ret rkb rke rkk rko rks rkt rle rll rlo rlr rls rlt rob roe rok rol roo ror ros rot rrb rrk rrl rrr rrs rrt rsb rse rsk rsl rso rsr rss rst rtb rte rtk rtl rto rtr rts rtt sbb sbe sbk sbl sbo sbr sbs sbt se- seb see sek sel seo ser ses set sk- skb ske skk skl sko skr sks skt slb sle slk sll slo slr sls slt sob soe sok sol soo sor sos sot sr- srb sre srk srl sro srr srs srt ss- ssb sse ssk ssl sso ssr sss sst stb ste stk stl sto str sts stt tbb tbe tbk tbl tbo tbr tbs tbt te- teb tee tek tel teo ter tes tet tkb tke tkk tkl tko tkr tks tkt tle tlk tll tlo tlr tls tlt to- tob toe tok tol too tor tos tot trb tre trk trl tro trr trs trt tsb tse tsk tsl tso tsr tss tst ttb tte ttk ttl tto ttr tts ttt