Problem:
Score : 200 points

Problem Statement

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 1

2 1 1 3

Sample Output 1

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.

Sample Input 2

1 2 3 4

Sample Output 2

0

Sample Input 3

2000000000 0 0 2000000000

Sample Output 3

2000000000

Solution in Java (OpenJDK 11.0.6) (judge verdict: Wrong Answer)

import java.util.Scanner;
 
public class Main {
	public static void main(String[] args){
		Scanner in = new Scanner(System.in);
		int A = in.nextInt();	//1が書かれたカードの枚数
		int B = in.nextInt();	//0が書かれたカードの枚数
		int C = in.nextInt();	//-1が書かれたカードの枚数
		int K = in.nextInt();	//取る枚数
		int max = 0;			//最大値
 
		if((K-A) < 0){			//取る枚数がA以下ならば
			max += 1*K;
		}else{
          	max += 1*A;
			K-=A;
		}
 		if((K-B) >= 0){			//取る枚数がB以上ならば
			K-=B;
		}
      	if(K > 0){				//取る枚数が1以上ならば
			max -= 1*K;
		}
 
		System.out.println(max);
	}
}