import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

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

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

        int N = sc.nextInt();
        if (N % 1000 == 0) System.out.println(0);
        else System.out.println(1000 - (N % 1000));
    } main {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        if (N % 1000 == 0) System.out.println(0);
        else System.out.println(1000 - (N % 1000));
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc 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 System.out System System.out 0 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 sc = new Scanner(System.in);

        int N = sc.nextInt();
        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 sc = new Scanner(System.in);

        int N = sc.nextInt();
        if (N % 1000 == 0) System.out.println(0);
        else System.out.println(1000 - (N % 1000));
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        if (N % 1000 == 0) System.out.println(0);
        else System.out.println(1000 - (N % 1000));
    }
}
