-al -ol a-a a-b a-c aaa aab aac aad aal aao ab- aba abb abc abd abl abo ac- aca acb acc acd acl aco ad- ada adb adc add adl ado al- ala alb alc ald all alo aoa aob aoc aod aol aoo baa bab bac bad bal bao bba bbb bbc bbd bbl bbo bca bcb bcc bcd bcl bco bda bdb bdc bdd bdl bdo bla blb blc bld bll blo boa bob boc bod bol boo c-- caa cab cac cad cal cao cba cbb cbc cbd cbl cbo cca ccb ccc ccd ccl cco cda cdb cdc cdd cdl cdo cl- cla clb clc cld cll clo co- coa cob coc cod col coo daa dab dac dad dal dao dba dbb dbc dbd dbl dbo dca dcb dcc dcd dcl dco dda ddb ddc ddd ddl ddo dl- dla dlb dlc dld dll dlo doa dob doc dod dol doo la- laa lab lac lad lal lao lba lbb lbc lbd lbl lbo lca lcb lcc lcd lcl lco lda ldb ldc ldd ldl ldo lla llb llc lld lll llo loa lob loc lod lol loo oaa oab oac oad oal oao ob- oba obb obc obd obl obo oc- oca ocb occ ocd ocl oco oda odb odc odd odl odo ola olb olc old oll olo oo- ooa oob ooc ood ool ooo