-er -ol bbb bbc bbe bbk bbl bbo bbr bcb bcc bce bck bcl bco bcr bcv be- beb bec bee bek bel beo ber bev bkb bkc bke bkk bkl bko bkr bkv blb blc ble blk bll blo blr blv bob boc boe bok bol boo bor bov brb bre brk brl bro brr brv bvb bvc bve bvk bvl bvo bvr bvv c-- cbb cbc cbe cbk cbl cbo cbr cbv ccb ccc cce cck ccl cco ccr ccv ce- ceb cec cee cek cel ceo cer cev ckb ckc cko cl- clb clc cle clk cll clo clr clv co- cob coc coe cok col coo cor cov crb crc cre crk crl cro crr crv cvb cvc cve cvk cvl cvo cvr cvv ebb ebc ebe ebk ebl ebo ebr ebv ec- ecb ecc ece eck ecl eco ecr ecv eeb eec eee eek eel eeo eer eev ekb ekc eke ekl eko ekr ekv elb elc ele elk ell elo elr elv eo- eob eoc eoe eok eol eoo eor erb erc ere erk erl ero err erv evb evc eve evl evo evr evv kbb kbc kbe kbk kbl kbo kbr kcb kcc kce kck kcl kcr ke- keb kec kee kek kel keo ker kev kkb kkc kke kkk kkl kkr kkv kl- klb klc klo klr klv kob koc koe kok kol koo kor krc krk krl kro krr krv kvb kvk kvo kvr kvv lbb lbc lbe lbk lbl lbo lbr lbv lcb lcc lce lck lcl lco lcr lcv leb lec lee lek lel leo ler lev lkb lkl lkr llb llc lle llk lll llo llr llv lob loc loe lok lol loo lor lov lrb lrc lrk lro lrr lrv lvb lvc lve lvl lvr lvv ob- obb obc obe obk obl obo obr obv oc- ocb occ ock ocl oco ocr ocv oeb oec oee oel oeo oer okb okc oke okk okl oko okr olb olc ole olk oll olo oo- oob ooc ook ool ooo oor oov or- orb orc ore ork orl oro orr orv ov- ovb ovc ove ovl ovo ovv rbb rbc rbe rbk rbl rbo rbr rcb rcc rce rcl rco rcr rcv re- reb rec ree rek rel reo rer rev rkb rkc rke rkk rko rkv rlc rle rll rlo rlr rob roc roe rok rol roo ror rov rrb rrc rrk rrl rrr rvb rvc rve rvl rvo rvr rvv v-e vbc vbk vbl vbo vbr vbv vcc vce vcl vco vcr veb vec vee vek vel veo ver vkb vl- vlb vlc vle vlk vll vlo vlv vob voc voe vok vol voo vor vov vrb vrc vre vrk vrr vvb vvc vvo vvr vvv