import java.util.Scanner;

public class Main {

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

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

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

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

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int s = sc.nextInt();
        int k = s + 1000;
        k = k % 1000;
        System.out.println((1000 - k) % 1000);
    }
}
