a-a a-b a-c aaa aab aac aaj aao aay ab- aba abb abc abj abo aby ac- aca acb acc acj aco acy aja ajb ajc ajj ajo ajy aoa aob aoc aoj aoo ay- aya ayc ayo baa bab bac baj bao bay bba bbb bbc bbo bby bca bcb bcc bcj bco bcy bja bjc bjj boa bob boc boj boo boy by- bya byc byj byo c-- c-j caa cab cac caj cao cay cba cbb cbc cbj cbo cby cca ccb ccc ccj cco cja cjb cjc co- coa cob coc coj coo coy cya cyb cyc cyo jaa jab jac jaj jao jay jba jbc jbj jbo jca jcb jcc jco jja jjb jjc jjj jjy joa job joc joj joo joy jyj oaa oab oac oaj oao ob- oba obb obc obj obo oby oc- oca ocb occ ocj oco oja ojb ojc ojo ojy oo- ooa oob ooc ooo oya oyo yaa yab yac yao yay ybc yby yca ycc yco ycy yob yoc yoj yoo yoy yyb yyc yyy