import java.util.Scanner;

public class Main {

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

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

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

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

public class Main {

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