a-a a-b aaa aab aag aah aar ab- aba abb abg abh abr ag- aga agb agg agh agr aha ahb ahg ahh ahr ar- ara arb arg arh arr baa bab bag bah bar bba bbb bbg bbh bbr bga bgb bgg bgh bgr bha bhb bhg bhh bhr bra brb brg brh brr gaa gab gag gah gar gba gbg gbh gbr gga ggb ggg ggh ggr gha ghb ghg ghh ghr gra grb grg grh grr haa hab hag hah har hba hbb hbg hbh hbr hga hgb hgg hgh hgr hha hhb hhg hhh hhr hr- hra hrb hrg hrh hrr ra- raa rab rag rah rar rba rbb rbg rbh rbr rga rgb rgg rgh rgr rh- rha rhb rhg rhh rhr rra rrb rrg rrh rrr