import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
      	int n= sc.nextInt();
      	int ans = (10000-n)%1000;
    System.out.println(""+ans);
}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
      	int n= sc.nextInt();
      	int ans = (10000-n)%1000;
    System.out.println(""+ans);
}
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
      	int n= sc.nextInt();
      	int ans = (10000-n)%1000;
    System.out.println(""+ans);
} main {
		Scanner sc = new Scanner(System.in);
      	int n= sc.nextInt();
      	int ans = (10000-n)%1000;
    System.out.println(""+ans);
} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n= sc.nextInt(); n sc.nextInt() sc.nextInt sc int ans = (10000-n)%1000; ans (10000-n)%1000 (10000-n) 10000 n 1000 System.out.println(""+ans) System.out.println System.out System System.out ""+ans "" ans String[] args args public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
      	int n= sc.nextInt();
      	int ans = (10000-n)%1000;
    System.out.println(""+ans);
}
} public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
      	int n= sc.nextInt();
      	int ans = (10000-n)%1000;
    System.out.println(""+ans);
}
} Main
import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
      	int n= sc.nextInt();
      	int ans = (10000-n)%1000;
    System.out.println(""+ans);
}
}