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.*;
public class Main{

    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int k = sc.nextInt();
        int cnt  =0;

        while(true){
        if(k>0&&a<k){
            cnt+=a;
            k-=a;
            if(k<=0){
                break;
            }
        }else if(k>0){
            cnt=a;
            k=0;
            if(k<=0){
                break;
            }
        }
        
        if(k>0&& b<k){
            k-=b;
            if(k<=0){
                break;
            }
        }else if(k>0){
            k=0;
            if(k<=0){
                break;
            }
        }
       // System.out.println(cnt);
        
        if(c!=0&&k>0&& c<k){
            cnt-=c;
            k=0;
            if(k<=0){
                break;
            }
        }else if(c!=0&&k>0){
            cnt-=k;
            k=0;
            if(k<=0){
                break;
            }
        }
    }
        System.out.println(cnt);
    


    }
}