import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
			int a = sc.nextInt();
			int b = 1000-a%1000;
			b = b==1000 ? 0:b;
			System.out.println(b);
	}	
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
			int a = sc.nextInt();
			int b = 1000-a%1000;
			b = b==1000 ? 0:b;
			System.out.println(b);
	}	
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
			int a = sc.nextInt();
			int b = 1000-a%1000;
			b = b==1000 ? 0:b;
			System.out.println(b);
	} main {
		Scanner sc = new Scanner(System.in);
			int a = sc.nextInt();
			int b = 1000-a%1000;
			b = b==1000 ? 0:b;
			System.out.println(b);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc int b = 1000-a%1000; b 1000-a%1000 1000 a%1000 a 1000 b = b==1000 ? 0:b b b==1000 ? 0:b b==1000 b 1000 0 b System.out.println(b) System.out.println System.out System System.out b String[] args args public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
			int a = sc.nextInt();
			int b = 1000-a%1000;
			b = b==1000 ? 0:b;
			System.out.println(b);
	}	
} public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
			int a = sc.nextInt();
			int b = 1000-a%1000;
			b = b==1000 ? 0:b;
			System.out.println(b);
	}	
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
			int a = sc.nextInt();
			int b = 1000-a%1000;
			b = b==1000 ? 0:b;
			System.out.println(b);
	}	
}
