a-a a-b a-z aaa aab aad aao aau aaz ab- aba abb abd abo abu abz ad- ada adb add ado adu adz aoa aob aod aoo aou au- aua aub aud auo auz az- aza azb azd azo azu azz b-u baa bab bad bao bau baz bba bbb bbd bbo bbu bda bdb bdd bdo bdu bdz boa bob bod boo bou boz bua bub bud buo buu buz bza bzd bzo bzu bzz daa dab dad dao dau daz dba dbb dbd dbo dbu dbz dda ddb ddd ddo ddu ddz doa dob dod doo dou doz dua dub dud duo duz dza dzb dzd dzo dzu oaa oab oad oao oau ob- oba obb obd obo obu oda odb odd odo odu oo- ooa oob ood ooo ou- oua oud ouo oza ozo ozu ozz ua- uaa uab uad uao uau uaz uba ubb ubo ubu uda udb udd udo udu uoa uob uod uoo uua uuu uza uzb uzo uzu zaa zab zad zao zaz zbb zo- zoa zob zod zoo zou zub zud zuz zzz