a-a a-b a-t aaa aab aag aao aat ab- aba abb abg abo abt ag- aga agb agg ago agt aoa aob aog aoo aot at- ata atb atg ato att baa bab bag bao bat bba bbb bbg bbo bbt bga bgb bgg bgo bgt boa bob bog boo bot bta btb btg bto btt gaa gab gag gao gat gba gbg gbo gbt gga ggb ggg ggo ggt goa gob gog goo got gta gtb gtg gto gtt oaa oab oag oao oat ob- oba obb obg obo obt oga ogg ogo ogt oo- ooa oob oog ooo oot ot- ota otb otg oto ott taa tab tag tao tat tba tbb tbg tbo tbt tga tgb tgg tgo tgt to- toa tob tog too tot tta ttb ttg tto ttt