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 JavaScript (Node.js 12.16.1) (judge verdict: Accepted)

function main(input) {
  const inputs =input.split('\n')
  const [N] = inputs[0].split(' ')
  if (N % 1000 === 0) {
    console.log(0)
  } else {
    console.log(
      (1000 - (N % 1000))
    )
  }
}

main(require('fs').readFileSync('/dev/stdin', 'utf8').trim())