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