Probability problem: two out of five lottery tickets win. Party A and Party B each draw one, and only Party B will win the prize.

1, No.2 has a prize.

Then A draws 3 first, and B draws 1.

And B got 1 first, and A got 3.

The results are exactly the same, A 3 B 1, which is the same situation.

So it only needs to be calculated once.