A - Payment

Time Limit: 2 sec / Memory Limit: 1024 MB

Score :$100100$points

Problem Statement

We will buy a product for$\mathrm{NN}$yen (the currency of Japan) at a shop.

If we use only$10001000$-yen bills to pay the price, how much change will we receive?

Assume we use the minimum number of bills required.

Constraints

• $\mathrm{1\le N\le 100001\le N\le 10000}$
• $\mathrm{NN}$is an integer.

Input

Input is given from Standard Input in the following format:

$\mathrm{NN}$

Output

Print the amount of change as an integer.

Sample Input 1Copy

1900

Sample Output 1Copy

100

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

Sample Input 2Copy

3000

Sample Output 2Copy

0

We can pay the exact price.

題意：給你一個數，算出找零的數(其實原文更容易看懂)

解題思路：對n用1k求餘如果餘數為0則不用找錢(給的錢剛好為1k的整數倍)，否則就要找1k-n%1k的零錢

程式碼如下：

#include<cstdio>
int main(void)
{
    int n;
    while(~scanf("%d",&n))
    printf("%d\n",n%1000==0?0:1000-n%1000);
    return 0
 
;
}