import java.util.Scanner;

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

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

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

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

} Main
import java.util.Scanner;

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

}