
import java.util.ArrayList;
import java.util.Scanner;


public class Main {
public static void main (String[] args){


	Scanner sc =new Scanner(System.in);
	ArrayList<Integer> list=new ArrayList<Integer>();


	while(sc.hasNextLine()) {
		list.add(Integer.parseInt(sc.nextLine()));
	}
	
	int thousand=list.get(0)/1000;
	
	if(list.get(0)%1000!=0) {
	int thousands=(int) Math.floor(thousand)+1;

	System.out.print(thousands*1000-list.get(0));
	}else {
		System.out.print(0);
	}
}}



/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