-er -ol bbb bbc bbe bbk bbl bbo bbr bbs bbt bcb bcc bce bck bcl bco bcr bcs bct be- beb bec bee bek bel beo ber bes bet bkb bkc bke bkk bkl bko bkr bks bkt blb blc ble blk bll blo blr bls blt bob boc boe bok bol boo bor bos bot brb bre brk brl bro brr brs brt bsb bsc bse bsk bsl bso bsr bss bst btb btc bte btk btl bto btr bts btt c-- cbb cbc cbe cbk cbl cbo cbr cbs cbt ccb ccc cce cck ccl cco ccr ccs cct ce- ceb cec cee cek cel ceo cer ces cet ckb ckc cko cks ckt cl- clb clc cle clk cll clo clr cls clt co- cob coc coe cok col coo cor cos cot crb crc cre crk crl cro crr crs crt csb csc cse csk csl cso csr css cst ctb ctc cte ctk ctl cto ctr cts ctt ebb ebc ebe ebk ebl ebo ebr ebs ebt ec- ecb ecc ece eck ecl eco ecr ecs ect eeb eec eee eek eel eeo eer ees eet ekb ekc eke ekl eko ekr eks ekt elb elc ele elk ell elo elr els elt eo- eob eoc eoe eok eol eoo eor eos eot erb erc ere erk erl ero err ers ert es- esb esc ese esk esl eso esr ess est etb etc ete etk etl eto etr ets ett k-t kbb kbc kbe kbk kbl kbo kbr kbs kcb kcc kce kck kcl kcr kcs kct ke- keb kec kee kek kel keo ker kes ket kkb kkc kke kkk kkl kkr kks kkt kl- klb klc klo klr kls klt kob koc koe kok kol koo kor kos kot krc krk krl kro krr krs krt ksb ksc kse ksk ksl kso ksr kss kst ktb ktc kte ktk ktl kto ktr kts ktt lbb lbc lbe lbk lbl lbo lbr lbs lbt lcb lcc lce lck lcl lco lcr lcs lct leb lec lee lek lel leo ler les let lkb lkl lkr lks lkt llb llc lle llk lll llo llr lls llt lob loc loe lok lol loo lor los lot lrb lrc lrk lro lrr lrs lrt lsb lsc lse lsk lsl lso lsr lss lst ltb ltc lte ltk ltl lto ltr lts ltt ob- obb obc obe obk obl obo obr obs obt oc- ocb occ ock ocl oco ocr ocs oct oeb oec oee oel oeo oer oes oet okb okc oke okk okl oko okr oks olb olc ole olk oll olo ols olt oo- oob ooc ook ool ooo oor oos oot or- orb orc ore ork orl oro orr ors ort os- osb osc ose osk osl oso osr oss ost ot- otb otc ote otk otl oto otr ots ott rbb rbc rbe rbk rbl rbo rbr rbs rbt rcb rcc rce rcl rco rcr rcs rct re- reb rec ree rek rel reo rer res ret rkb rkc rke rkk rko rks rkt rlc rle rll rlo rlr rls rlt rob roc roe rok rol roo ror ros rot rrb rrc rrk rrl rrr rrs rrt rsb rsc rse rsk rsl rso rsr rss rst rtb rtc rte rtk rtl rto rtr rts rtt sbb sbc sbe sbk sbl sbo sbr sbs sbt scb scc sce sck scl sco scr scs sct se- seb sec see sek sel seo ser ses set sk- skb skc ske skk skl sko skr sks skt slb slc sle slk sll slo slr sls slt sob soc soe sok sol soo sor sos sot sr- srb src sre srk srl sro srr srs srt ss- ssb ssc sse ssk ssl sso ssr sss sst stb stc ste stk stl sto str sts stt tbb tbc tbe tbk tbl tbo tbr tbs tbt tcb tcc tce tck tcl tco tcr tcs tct te- teb tec tee tek tel teo ter tes tet tkb tkc tke tkk tkl tko tkr tks tkt tlc tle tlk tll tlo tlr tls tlt to- tob toc toe tok tol too tor tos tot trb trc tre trk trl tro trr trs trt tsb tsc tse tsk tsl tso tsr tss tst ttb ttc tte ttk ttl tto ttr tts ttt