-ol bbb bbc bbe bbk bbl bbo bcb bcc bce bck bcl bco bcv be- beb bec bee bek bel beo bev bkb bkc bke bkk bkl bko bkv blb blc ble blk bll blo blv bob boc boe bok bol boo bov bvb bvc bve bvk bvl bvo bvv c-- cbb cbc cbe cbk cbl cbo cbv ccb ccc cce cck ccl cco ccv ce- ceb cec cee cek cel ceo cev ckb ckc cko cl- clb clc cle clk cll clo clv co- cob coc coe cok col coo cov cvb cvc cve cvk cvl cvo cvv ebb ebc ebe ebk ebl ebo ebv ec- ecb ecc ece eck ecl eco ecv eeb eec eee eek eel eeo eev ekb ekc eke ekl eko ekv elb elc ele elk ell elo elv eo- eob eoc eoe eok eol eoo evb evc eve evl evo evv kbb kbc kbe kbk kbl kbo kcb kcc kce kck kcl ke- keb kec kee kek kel keo kev kkb kkc kke kkk kkl kkv kl- klb klc klo klv kob koc koe kok kol koo kvb kvk kvo kvv lbb lbc lbe lbk lbl lbo lbv lcb lcc lce lck lcl lco lcv leb lec lee lek lel leo lev lkb lkl llb llc lle llk lll llo llv lob loc loe lok lol loo lov lvb lvc lve lvl lvv ob- obb obc obe obk obl obo obv oc- ocb occ ock ocl oco ocv oeb oec oee oel oeo okb okc oke okk okl oko olb olc ole olk oll olo oo- oob ooc ook ool ooo oov ov- ovb ovc ove ovl ovo ovv v-e vbc vbk vbl vbo vbv vcc vce vcl vco veb vec vee vek vel veo vkb vl- vlb vlc vle vlk vll vlo vlv vob voc voe vok vol voo vov vvb vvc vvo vvv