-ol bbb bbe bbf bbk bbl bbo bbx be- beb bee bef bek bel beo bex bfb bfe bff bfl bfo bfx bkb bke bkf bkk bkl bko bkx blb ble blf blk bll blo blx bob boe bof bok bol boo box bxb bxl bxo bxx ebb ebe ebf ebk ebl ebo ebx eeb eee eef eek eel eeo eex ef- efb efe eff efl efo efx ekb eke ekf ekl eko elb ele elf elk ell elo elx eo- eob eoe eof eok eol eoo ex- exe exl exo exx fbb fbe fbf fbk fbl fbo fbx feb fee fef fek fel feo fex ffe fff ffk ffl ffo ffx fkb fkf fkk fkl flb fle flf fll flo flx fob foe fof fok fol foo fox fxe fxx kbb kbe kbf kbk kbl kbo kbx ke- keb kee kef kek kel keo kex kff kfo kfx kkb kke kkk kkl kl- klb klf klo klx kob koe kof kok kol koo kxl kxo lbb lbe lbf lbk lbl lbo lbx leb lee lef lek lel leo lex lfb lfe lff lfk lfl lfo lfx lkb lkl llb lle llf llk lll llo lob loe lof lok lol loo lox lxo lxx ob- obb obe obf obk obl obo obx oeb oee oef oel oeo oex of- ofb ofe off ofl ofo ofx okb oke okk okl oko olb ole olf olk oll olo oo- oob oof ook ool ooo oox ox- oxb oxf oxo oxx xbe xbl xbx xee xel xex xfe xfl xfx xkb xke xkl xlb xlf xof xok xoo xox xxl xxo xxx