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 C (GCC 9.2.1) (judge verdict: Wrong Answer)

#include<stdio.h>
int main(void)
{
    int a,b,c,k;
    scanf("%d %d %d %d",&a,&b,&c,&k);
    int i=0,cnt=0,j,l,max=0,m,v;

    for(j=0;j<=a;j++){
        for(v=0;v<=b;v++){
            for(l=0;l<=c;l++){
                if(j+v+l==k){
                    if(1*j+k*0+(-1)*l>max){
                        max=1*j+k*0+(-1)*l;
                    }
                }
            }
        }
    }
    printf("%d\n",max);
    return 0;
}