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<bits/stdc++.h>
using namespace std;
int main()
{
    int n,c,d;
    cin>>n;
    if(n%1000==0)
    {
        cout<<0<<endl;
    }
    else
    {
        c=n/1000;
        d=((c+1)*1000)-n;
        cout<<d<<endl;
    }
}