-ol bbb bbf bbl bbn bbo bfb bff bfl bfn bfo blb blf bll bln blo bnb bnf bnl bnn bno bob bof bol bon boo fbb fbf fbl fbn fbo fff ffl ffn ffo flb flf fll fln flo fnb fnf fnl fnn fob fof fol fon foo lbb lbf lbl lbo lfb lff lfl lfn lfo llb llf lll lln llo lnb lnl lnn lno lob lof lol lon loo nbb nbf nbl nbn nbo nfb nff nfl nfn nfo nlb nlf nll nln nlo nnb nnf nnl nnn nno no- nob nof nol non noo ob- obb obf obl obn obo of- ofb off ofl ofn ofo olb olf oll oln olo on- onb onf onl onn ono oo- oob oof ool oon ooo