/**
 * A
 */
import java.io.*;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        InputStream in = System.in;
        Scanner scanner = new Scanner(in);
    
        int next = scanner.nextInt();
        int left = 1000 - (next % 1000);
        System.out.println(left == 1000 ? 0 : left);
        scanner.close();
    }

}
/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