a-a a-b aaa aab aag aah aan ab- aba abb abg abh abn ag- aga agb agg agh agn aha ahb ahg ahh ahn an- ana anb ang anh ann baa bab bag bah ban bba bbb bbg bbh bbn bga bgb bgg bgh bgn bha bhb bhg bhh bna bnb bng bnn gaa gab gag gah gan gba gbg gbh gbn gga ggb ggg ggh ggn gha ghb ghg ghh ghn gna gnb gnn haa hab hag hah han hba hbb hbg hbh hbn hga hgb hgg hgh hgn hha hhb hhg hhh hhn hna hnb hng hnh hnn naa nab nag nah nan nba nbb nbg nbn nga ngb ngg ngh ngn nha nhb nhg nhh nhn nna nnb nng nnh nnn