First I got TL on #24
Then I got WA on #24
Are there large answer?
 Thanks.

No. No large answer. How could it be large? Everything is quite simple. You can solve this problem occasionally, even if not think much.

I try to took "j" goods for A$ and  goods for B$ on rest money.
Then I try to took "j" goods for B$ and goods for A$ on rest money.
0<="j"<=min(n/a,b)
What's wrong?
My single idea :my code can generate negative numbers as answer.
I don't understand anything...

got AC