a-a a-b a-z aaa aab aag aar aaz ab- aba abb abg abr abz ag- aga agb agg agr agz ar- ara arb arg arr arz az- aza azb azg azz baa bab bag bar baz bba bbb bbg bbr bga bgb bgg bgr bgz bra brb brg brr brz bza bzr bzz gaa gab gag gar gaz gba gbg gbr gbz gga ggb ggg ggr ggz gra grb grg grr gza gzr ra- raa rab rag rar raz rba rbb rbg rbr rga rgb rgg rgr rra rrb rrg rrr rza rzb z-g zaa zab zag zar zaz zbb zbr zgb zgg zzr zzz