a-a a-b a-z aaa aab aag aao aas aaz ab- aba abb abg abo abs abz ag- aga agb agg ago ags agz aoa aob aog aoo aos as- asa asb asg aso ass asz az- aza azb azg azo azs azz baa bab bag bao bas baz bba bbb bbg bbo bbs bga bgb bgg bgo bgs bgz boa bob bog boo bos boz bsa bsb bsg bso bss bza bzo bzs bzz gaa gab gag gao gas gaz gba gbg gbo gbs gbz gga ggb ggg ggo ggs ggz goa gob gog goo gos goz gsa gsb gsg gso gss gza gzo oaa oab oag oao oas ob- oba obb obg obo obs oga ogg ogo ogs oo- ooa oob oog ooo oos os- osa osb osg oso oss oza ozo ozs ozz saa sab sag sao sas saz sba sbb sbg sbo sbs sga sgb sgg sgo sgs soa sob sog soo sos soz ss- ssa ssb ssg sso sss ssz sza z-g zaa zab zag zao zas zaz zbb zbs zgb zgg zgs zo- zoa zob zog zoo zos zsa zsg zsz zzs zzz