-al -ol a-a a-b aaa aab aal aao aav ab- aba abb abl abo abv al- ala alb all alo alv aoa aob aol aoo aov av- ava avb avl avo baa bab bal bao bav bba bbb bbl bbo bla blb bll blo blv boa bob bol boo bov bva bvb bvl bvo bvv la- laa lab lal lao lav lba lbb lbl lbo lbv lla llb lll llo llv loa lob lol loo lov lva lvb lvl lvv oaa oab oal oao oav ob- oba obb obl obo obv ola olb oll olo oo- ooa oob ool ooo oov ov- ova ovb ovl ovo ovv v-a vaa vab val vao vav vba vbl vbo vbv vl- vla vlb vll vlo vlv voa vob vol voo vov vva vvb vvo vvv