a-a a-b a-c aaa aab aac aag aao aar aay ab- aba abb abc abg abo abr aby ac- aca acb acc acg aco acr acy ag- aga agb agc agg ago agr agy aoa aob aoc aog aoo aor ar- ara arb arc arg aro arr ary ay- aya ayc ayo ayr baa bab bac bag bao bar bay bba bbb bbc bbg bbo bbr bby bca bcb bcc bcg bco bcr bcy bga bgb bgc bgg bgo bgr boa bob boc bog boo bor boy bra brb brg bro brr bry by- bya byc byg byo byr c-- caa cab cac cag cao car cay cba cbb cbc cbg cbo cbr cby cca ccb ccc ccg cco ccr cga cgb cgc cgg cgo cgr cgy co- coa cob coc cog coo cor coy cra crb crc crg cro crr cry cya cyb cyc cyg cyo cyr gaa gab gac gag gao gar gay gba gbc gbg gbo gbr gby gca gcb gcc gcg gco gcr gga ggb ggc ggg ggo ggr goa gob goc gog goo gor goy gra grb grc grg gro grr gry gy- gya gyb gyo gyr oaa oab oac oag oao oar ob- oba obb obc obg obo obr oby oc- oca ocb occ ocg oco ocr oga ogc ogg ogo ogy oo- ooa oob ooc oog ooo oor or- ora orb orc org oro orr ory oya oyo ra- raa rab rac rag rao rar ray rba rbb rbc rbg rbo rbr rca rcb rcc rcg rco rcr rga rgb rgc rgg rgo rgr roa rob roc rog roo ror roy rra rrb rrc rrg rrr ry- rya ryc ryg ryo ryr ryy yaa yab yac yag yao yar yay ybc ybg ybr yby yca ycc yco ycy yga ygc ygo yob yoc yog yoo yor yoy yra yrc yrg yro yyb yyc yyg yyy