题目描述
We have A cards, each of which has an integer 1 written on it. Similarly, we also have B cards with 0s and C cards with -1s.
We will pick up K among these cards. What is the maximum possible sum of the numbers written on the cards chosen?
-----Constraints-----
- All values in input are integers.
- $0 \leq A, B, C$
- $1 \leq K \leq A + B + C \leq 2 \times 10^9$
-----Input-----
Input is given from Standard Input in the following format:
A B C K
-----Output-----
Print the maximum possible sum of the numbers written on the cards chosen.
-----Sample Input-----
2 1 1 3
-----Sample Output-----
2
Consider picking up two cards with 1s and one card with a 0.
In this case, the sum of the numbers written on the cards is 2, which is the maximum possible value.
输入格式
见题面
输出格式
见题面