a-a a-b a-t aaa aab aag aao aat aay ab- aba abb abg abo abt aby ag- aga agb agg ago agt agy aoa aob aog aoo aot at- ata atb atg ato att ay- aya ayo ayt baa bab bag bao bat bay bba bbb bbg bbo bbt bby bga bgb bgg bgo bgt boa bob bog boo bot boy bta btb btg bto btt bty by- bya byg byo byt gaa gab gag gao gat gay gba gbg gbo gbt gby gga ggb ggg ggo ggt goa gob gog goo got goy gta gtb gtg gto gtt gty gy- gya gyb gyo oaa oab oag oao oat ob- oba obb obg obo obt oby oga ogg ogo ogt ogy oo- ooa oob oog ooo oot ot- ota otb otg oto ott oya oyo taa tab tag tao tat tay tba tbb tbg tbo tbt tga tgb tgg tgo tgt tgy to- toa tob tog too tot toy tta ttb ttg tto ttt tty tya tyg tyo tyt yaa yab yag yao yat yay ybg yby yga ygo yob yog yoo yot yoy yta yto ytt yyb yyg yyt yyy