-er -ol bbb bbc bbe bbk bbl bbo bbr bbt bcb bcc bce bck bcl bco bcr bct be- beb bec bee bek bel beo ber bet bkb bkc bke bkk bkl bko bkr bkt blb blc ble blk bll blo blr blt bob boc boe bok bol boo bor bot brb bre brk brl bro brr brt btb btc bte btk btl bto btr btt c-- cbb cbc cbe cbk cbl cbo cbr cbt ccb ccc cce cck ccl cco ccr cct ce- ceb cec cee cek cel ceo cer cet ckb ckc cko ckt cl- clb clc cle clk cll clo clr clt co- cob coc coe cok col coo cor cot crb crc cre crk crl cro crr crt ctb ctc cte ctk ctl cto ctr ctt ebb ebc ebe ebk ebl ebo ebr ebt ec- ecb ecc ece eck ecl eco ecr ect eeb eec eee eek eel eeo eer eet ekb ekc eke ekl eko ekr ekt elb elc ele elk ell elo elr elt eo- eob eoc eoe eok eol eoo eor eot erb erc ere erk erl ero err ert etb etc ete etk etl eto etr ett k-t kbb kbc kbe kbk kbl kbo kbr kcb kcc kce kck kcl kcr kct ke- keb kec kee kek kel keo ker ket kkb kkc kke kkk kkl kkr kkt kl- klb klc klo klr klt kob koc koe kok kol koo kor kot krc krk krl kro krr krt ktb ktc kte ktk ktl kto ktr ktt lbb lbc lbe lbk lbl lbo lbr lbt lcb lcc lce lck lcl lco lcr lct leb lec lee lek lel leo ler let lkb lkl lkr lkt llb llc lle llk lll llo llr llt lob loc loe lok lol loo lor lot lrb lrc lrk lro lrr lrt ltb ltc lte ltk ltl lto ltr ltt ob- obb obc obe obk obl obo obr obt oc- ocb occ ock ocl oco ocr oct oeb oec oee oel oeo oer oet okb okc oke okk okl oko okr olb olc ole olk oll olo olt oo- oob ooc ook ool ooo oor oot or- orb orc ore ork orl oro orr ort ot- otb otc ote otk otl oto otr ott rbb rbc rbe rbk rbl rbo rbr rbt rcb rcc rce rcl rco rcr rct re- reb rec ree rek rel reo rer ret rkb rkc rke rkk rko rkt rlc rle rll rlo rlr rlt rob roc roe rok rol roo ror rot rrb rrc rrk rrl rrr rrt rtb rtc rte rtk rtl rto rtr rtt tbb tbc tbe tbk tbl tbo tbr tbt tcb tcc tce tck tcl tco tcr tct te- teb tec tee tek tel teo ter tet tkb tkc tke tkk tkl tko tkr tkt tlc tle tlk tll tlo tlr tlt to- tob toc toe tok tol too tor tot trb trc tre trk trl tro trr trt ttb ttc tte ttk ttl tto ttr ttt