-al -ol a-a a-b aaa aab aal aan aao ab- aba abb abl abn abo al- ala alb all aln alo an- ana anb anl ann ano aoa aob aol aon aoo baa bab bal ban bao bba bbb bbl bbn bbo bla blb bll bln blo bna bnb bnl bnn bno boa bob bol bon boo la- laa lab lal lan lao lba lbb lbl lbo lla llb lll lln llo lna lnb lnl lnn lno loa lob lol lon loo naa nab nal nan nao nba nbb nbl nbn nbo nla nlb nll nln nlo nna nnb nnl nnn nno no- noa nob nol non noo oaa oab oal oan oao ob- oba obb obl obn obo ola olb oll oln olo on- ona onb onl onn ono oo- ooa oob ool oon ooo