a-a a-b aaa aab aag aao aar aay ab- aba abb abg abo abr aby ag- aga agb agg ago agr agy aoa aob aog aoo aor ar- ara arb arg aro arr ary ay- aya ayo ayr baa bab bag bao bar bay bba bbb bbg bbo bbr bby bga bgb bgg bgo bgr boa bob bog boo bor boy bra brb brg bro brr bry by- bya byg byo byr gaa gab gag gao gar gay gba gbg gbo gbr gby gga ggb ggg ggo ggr goa gob gog goo gor goy gra grb grg gro grr gry gy- gya gyb gyo gyr oaa oab oag oao oar ob- oba obb obg obo obr oby oga ogg ogo ogy oo- ooa oob oog ooo oor or- ora orb org oro orr ory oya oyo ra- raa rab rag rao rar ray rba rbb rbg rbo rbr rga rgb rgg rgo rgr roa rob rog roo ror roy rra rrb rrg rrr ry- rya ryg ryo ryr ryy yaa yab yag yao yar yay ybg ybr yby yga ygo yob yog yoo yor yoy yra yrg yro yyb yyg yyy