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: Runtime Error)

//AtCoder Biginner Contest 173 A問題

#include <stdio.h>

int main(void) {
    int n, m;

    scanf("%d", &n);

    m = n % 1000;

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

    return 0;
}