-al -ol a-a a-b aaa aab aad aal aao ab- aba abb abd abl abo ad- ada adb add adl ado al- ala alb ald all alo aoa aob aod aol aoo baa bab bad bal bao bba bbb bbd bbl bbo bda bdb bdd bdl bdo bla blb bld bll blo boa bob bod bol boo daa dab dad dal dao dba dbb dbd dbl dbo dda ddb ddd ddl ddo dl- dla dlb dld dll dlo doa dob dod dol doo la- laa lab lad lal lao lba lbb lbd lbl lbo lda ldb ldd ldl ldo lla llb lld lll llo loa lob lod lol loo oaa oab oad oal oao ob- oba obb obd obl obo oda odb odd odl odo ola olb old oll olo oo- ooa oob ood ool ooo