import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        int n, res;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        if (n % 1000 != 0) {
            res = 1000 - n % 1000;
            System.out.println(res);

        } else System.out.println("0");

    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        int n, res;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        if (n % 1000 != 0) {
            res = 1000 - n % 1000;
            System.out.println(res);

        } else System.out.println("0");

    }
} Main public static void main(String[] args) {
        int n, res;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        if (n % 1000 != 0) {
            res = 1000 - n % 1000;
            System.out.println(res);

        } else System.out.println("0");

    } main {
        int n, res;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        if (n % 1000 != 0) {
            res = 1000 - n % 1000;
            System.out.println(res);

        } else System.out.println("0");

    } int n n res; res Scanner sc = new Scanner(System.in); sc new Scanner(System.in) n = sc.nextInt() n sc.nextInt() sc.nextInt sc if (n % 1000 != 0) {
            res = 1000 - n % 1000;
            System.out.println(res);

        } else System.out.println("0"); n % 1000 != 0 n % 1000 n 1000 0 {
            res = 1000 - n % 1000;
            System.out.println(res);

        } res = 1000 - n % 1000 res 1000 - n % 1000 1000 n % 1000 n 1000 System.out.println(res) System.out.println System.out System System.out res System.out.println("0") System.out.println System.out System System.out "0" String[] args args public class Main {
    public static void main(String[] args) {
        int n, res;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        if (n % 1000 != 0) {
            res = 1000 - n % 1000;
            System.out.println(res);

        } else System.out.println("0");

    }
} public class Main {
    public static void main(String[] args) {
        int n, res;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        if (n % 1000 != 0) {
            res = 1000 - n % 1000;
            System.out.println(res);

        } else System.out.println("0");

    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        int n, res;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        if (n % 1000 != 0) {
            res = 1000 - n % 1000;
            System.out.println(res);

        } else System.out.println("0");

    }
}
