a-a a-b a-c a-z aaa aab aac aad aao aaz ab- aba abb abc abd abo abz ac- aca acb acc acd aco acz ad- ada adb adc add ado adz aoa aob aoc aod aoo az- aza azb azd azo azz baa bab bac bad bao baz bba bbb bbc bbd bbo bca bcb bcc bcd bco bcz bda bdb bdc bdd bdo bdz boa bob boc bod boo boz bza bzd bzo bzz c-- caa cab cac cad cao caz cba cbb cbc cbd cbo cbz cca ccb ccc ccd cco ccz cda cdb cdc cdd cdo cdz co- coa cob coc cod coo coz cz- czc czd czo daa dab dac dad dao daz dba dbb dbc dbd dbo dbz dca dcb dcc dcd dco dda ddb ddc ddd ddo ddz doa dob doc dod doo doz dza dzb dzd dzo oaa oab oac oad oao ob- oba obb obc obd obo oc- oca ocb occ ocd oco ocz oda odb odc odd odo oo- ooa oob ooc ood ooo oza ozo ozz zaa zab zac zad zao zaz zbb zbc zco zo- zoa zob zoc zod zoo zzz