import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
        int X = sc.nextInt();
        int ans = (10000 - X) % 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 X = sc.nextInt();
        int ans = (10000 - X) % 1000;
        System.out.println(ans);
    } 
} Main public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
        int X = sc.nextInt();
        int ans = (10000 - X) % 1000;
        System.out.println(ans);
    } main {
        Scanner sc= new Scanner(System.in);
        int X = sc.nextInt();
        int ans = (10000 - X) % 1000;
        System.out.println(ans);
    } Scanner sc= new Scanner(System.in); sc new Scanner(System.in) int X = sc.nextInt(); X sc.nextInt() sc.nextInt sc int ans = (10000 - X) % 1000; ans (10000 - X) % 1000 (10000 - X) 10000 X 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 X = sc.nextInt();
        int ans = (10000 - X) % 1000;
        System.out.println(ans);
    } 
} public class Main {
    public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
        int X = sc.nextInt();
        int ans = (10000 - X) % 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 X = sc.nextInt();
        int ans = (10000 - X) % 1000;
        System.out.println(ans);
    } 
}