a-a a-b a-z aaa aab aad aao aap aaz ab- aba abb abd abo abp abz ad- ada adb add ado adp adz aoa aob aod aoo aop ap- apa apb apd apo app az- aza azb azd azo azp azz b-p baa bab bad bao bap baz bba bbb bbd bbo bbp bda bdb bdd bdo bdp bdz boa bob bod boo bop boz bpa bpb bpd bpo bpp bza bzd bzo bzp bzz daa dab dad dao dap daz dba dbb dbd dbo dbp dbz dda ddb ddd ddo ddp ddz doa dob dod doo dop doz dpa dpb dpd dpo dpp dpz dza dzb dzd dzo dzp oaa oab oad oao oap ob- oba obb obd obo obp oda odb odd odo odp oo- ooa oob ood ooo oop op- opa opb opd opo opp oza ozo ozz p-p paa pab pad pao pap paz pba pbb pbd pbo pbp pbz pda pdb pdd pdo pdp pdz poa pob pod poo pop poz ppa ppb ppd ppo ppp ppz pzp zaa zab zad zao zap zaz zbb zo- zoa zob zod zoo zpo zpp zzz