a-a a-b a-z aaa aab aag aao aar aax aaz ab- aba abb abg abo abr abx abz ag- aga agb agg ago agr agx agz aoa aob aog aoo aor aox ar- ara arb arg aro arr arx arz ax- axa axo axr axx az- aza azb azg azo azx azz baa bab bag bao bar bax baz bba bbb bbg bbo bbr bbx bga bgb bgg bgo bgr bgx bgz boa bob bog boo bor box boz bra brb brg bro brr brx brz bxb bxo bxx bza bzo bzr bzz gaa gab gag gao gar gaz gba gbg gbo gbr gbx gbz gga ggb ggg ggo ggr ggz goa gob gog goo gor gox goz gra grb grg gro grr grx gxa gza gzo gzr oaa oab oag oao oar oax ob- oba obb obg obo obr obx oga ogg ogo ogx oo- ooa oob oog ooo oor oox or- ora orb org oro orr orx orz ox- oxa oxb oxo oxx oza ozo ozz ra- raa rab rag rao rar rax raz rba rbb rbg rbo rbr rbx rga rgb rgg rgo rgr rgx roa rob rog roo ror rox roz rra rrb rrg rrr rxr rza rzb rzo xaa xag xar xbr xbx xoa xog xoo xor xox xrx xxo xxx z-g zaa zab zag zao zar zax zaz zbb zbr zgb zgg zo- zoa zob zog zoo zor zox zro zxx zzr zzx zzz