import java.util.*;
import java.lang.*;

public class Main
{
    public static void main (String[] args)
    {
        // your code goes here
        Scanner s = new Scanner(System.in);
        int t = s.nextInt();
        System.out.println((1000-t%1000)%1000);
    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz