Problem:
Score : 100 points

Problem Statement

We will buy a product for N yen (the currency of Japan) at a shop.

If we use only 1000-yen bills to pay the price, how much change will we receive?

Assume we use the minimum number of bills required.

Constraints

1 \leq N \leq 10000

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the amount of change as an integer.

Sample Input 1

1900

Sample Output 1

100

We will use two 1000-yen bills to pay the price and receive 100 yen in change.

Sample Input 2

3000

Sample Output 2

0

We can pay the exact price.

Solution in C (GCC 9.2.1) (judge verdict: Accepted)

#include <stdio.h>

int main(){
    int n;
    int qdade;

    scanf("%d",&n);

    if(n%1000==0){
        printf("0\n");
    }else{
        n = (1000 - n%1000);
        printf("%d\n",n);
    }





    return 0;
}