//package  com.company;

import java.util.Scanner;

public class Main{

    public static void main(String[] args) {
       Scanner sc=new Scanner(System.in);
       int number=sc.nextInt();
       int val=number/1000;
       if(number%1000!=0){
           val+=1;
       }else{

       }
        System.out.println(1000*val-number);
    }
}
/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