OJ Board

Hi,
I have tried all inputs in this thread, and my solution returns corectly all of them. I have no ideea why do i get WA. Are there any trick cases?, What corner cases have you found?

some IO :

7
a
b
c
d
e
f
g
7
a b
c b
d b
e f
f d
e g
f g
7
a
b
c
d
e
f
g
7
a b
c b
d b
e d
f d
g e
g f
0


mine ...