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: Time Limit Exceeded)


import java.util.*;

public class Main{
    public static void main(String[]args){
      Scanner scan = new Scanner(System.in);

      long a = scan.nextInt();
      long b = scan.nextInt();
      long c = scan.nextInt();
      long k = scan.nextInt();

      long result= 0;


      for(int i=0; i<k; i++){
          if(a>0){
              result++;
              a--;
          } else if (b>0) {
              result += 0;
              b--;
          } else if (c>0){
              result--;
              c--;
          }
      }

        System.out.println(result);

    }
}