a-a a-b a-z aaa aab aag aao aar aaz ab- aba abb abg abo abr abz ag- aga agb agg ago agr agz aoa aob aog aoo aor ar- ara arb arg aro arr arz az- aza azb azg azo azz baa bab bag bao bar baz bba bbb bbg bbo bbr bga bgb bgg bgo bgr bgz boa bob bog boo bor boz bra brb brg bro brr brz bza bzo bzr bzz gaa gab gag gao gar gaz gba gbg gbo gbr gbz gga ggb ggg ggo ggr ggz goa gob gog goo gor goz gra grb grg gro grr gza gzo gzr oaa oab oag oao oar ob- oba obb obg obo obr oga ogg ogo oo- ooa oob oog ooo oor or- ora orb org oro orr orz oza ozo ozz ra- raa rab rag rao rar raz rba rbb rbg rbo rbr rga rgb rgg rgo rgr roa rob rog roo ror roz rra rrb rrg rrr rza rzb rzo z-g zaa zab zag zao zar zaz zbb zbr zgb zgg zo- zoa zob zog zoo zor zro zzr zzz