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: Accepted)

#include<stdio.h>
#include<string.h>

int main()
{
    long long int a,b,c,k,ans,ama ;
    int i,j ;
    long long int count=0 ;
    char s[485878],t[84623] ;
   scanf("%lld %lld %lld %lld",&a,&b,&c,&k) ;
   if(k<=a)
    count=k ;
   else
   {
    while(k!=0)
   {
     k=k-a ;
     count=count+a ;
     for(i=0 ; i<b ;i++)
     {
         k=k-1 ;
         if(k==0)
            break ;
     }
     if(k!=0)
     {
         for(i=0 ; i<c ;i++)
     {
         k=k-1 ;
         count=count-1 ;
         if(k==0)
            break ;
     }
     }

   }

    }
    printf("%lld",count)  ;
return 0 ;
}