import java.util.Scanner;

public class Main {
  public static void main(String args[]) {
    Scanner input = new Scanner(System.in);
    Integer N = Integer.valueOf(input.nextLine());
    if (N % 1000 == 0) {
      System.out.println(0);
    }
    else {
      System.out.println(1000 - N % 1000);
    }
  }
} import java.util.Scanner; Scanner java.util public class Main {
  public static void main(String args[]) {
    Scanner input = new Scanner(System.in);
    Integer N = Integer.valueOf(input.nextLine());
    if (N % 1000 == 0) {
      System.out.println(0);
    }
    else {
      System.out.println(1000 - N % 1000);
    }
  }
} Main public static void main(String args[]) {
    Scanner input = new Scanner(System.in);
    Integer N = Integer.valueOf(input.nextLine());
    if (N % 1000 == 0) {
      System.out.println(0);
    }
    else {
      System.out.println(1000 - N % 1000);
    }
  } main {
    Scanner input = new Scanner(System.in);
    Integer N = Integer.valueOf(input.nextLine());
    if (N % 1000 == 0) {
      System.out.println(0);
    }
    else {
      System.out.println(1000 - N % 1000);
    }
  } Scanner input = new Scanner(System.in); input new Scanner(System.in) Integer N = Integer.valueOf(input.nextLine()); N Integer.valueOf(input.nextLine()) Integer.valueOf Integer input.nextLine() input.nextLine input if (N % 1000 == 0) {
      System.out.println(0);
    }
    else {
      System.out.println(1000 - N % 1000);
    } N % 1000 == 0 N % 1000 N 1000 0 {
      System.out.println(0);
    } System.out.println(0) System.out.println System.out System System.out 0 {
      System.out.println(1000 - N % 1000);
    } System.out.println(1000 - N % 1000) System.out.println System.out System System.out 1000 - N % 1000 1000 N % 1000 N 1000 String args[] args public class Main {
  public static void main(String args[]) {
    Scanner input = new Scanner(System.in);
    Integer N = Integer.valueOf(input.nextLine());
    if (N % 1000 == 0) {
      System.out.println(0);
    }
    else {
      System.out.println(1000 - N % 1000);
    }
  }
} public class Main {
  public static void main(String args[]) {
    Scanner input = new Scanner(System.in);
    Integer N = Integer.valueOf(input.nextLine());
    if (N % 1000 == 0) {
      System.out.println(0);
    }
    else {
      System.out.println(1000 - N % 1000);
    }
  }
} Main
import java.util.Scanner;

public class Main {
  public static void main(String args[]) {
    Scanner input = new Scanner(System.in);
    Integer N = Integer.valueOf(input.nextLine());
    if (N % 1000 == 0) {
      System.out.println(0);
    }
    else {
      System.out.println(1000 - N % 1000);
    }
  }
}