a-a a-b aaa aab aag aah aay ab- aba abb abg abh aby ag- aga agb agg agh agy aha ahb ahg ahh ahy ay- aya ayh baa bab bag bah bay bba bbb bbg bbh bby bga bgb bgg bgh bha bhb bhg bhh by- bya byg byh gaa gab gag gah gay gba gbg gbh gby gga ggb ggg ggh gha ghb ghg ghh gy- gya gyb haa hab hag hah hay hba hbb hbg hbh hby hga hgb hgg hgh hgy hha hhb hhg hhh hhy hy- hya hyb hyg hyh hyy yaa yab yag yah yay ybg yby yga yha yyb yyg yyy