
import java.util.Scanner;

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

        Integer N = sc.nextInt();

        Integer ans = 0;
        if (N%1000 != 0) {// N が1000で割り切れないとき
            ans = (N/1000 + 1)*1000 - N;
        }

        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);

        Integer N = sc.nextInt();

        Integer ans = 0;
        if (N%1000 != 0) {// N が1000で割り切れないとき
            ans = (N/1000 + 1)*1000 - N;
        }

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

        Integer N = sc.nextInt();

        Integer ans = 0;
        if (N%1000 != 0) {// N が1000で割り切れないとき
            ans = (N/1000 + 1)*1000 - N;
        }

        System.out.println(ans);
    } main {
      Scanner sc = new Scanner(System.in);

        Integer N = sc.nextInt();

        Integer ans = 0;
        if (N%1000 != 0) {// N が1000で割り切れないとき
            ans = (N/1000 + 1)*1000 - N;
        }

        System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) Integer N = sc.nextInt(); N sc.nextInt() sc.nextInt sc Integer ans = 0; ans 0 if (N%1000 != 0) {// N が1000で割り切れないとき
            ans = (N/1000 + 1)*1000 - N;
        } N%1000 != 0 N%1000 N 1000 0 {// N が1000で割り切れないとき
            ans = (N/1000 + 1)*1000 - N;
        } ans = (N/1000 + 1)*1000 - N ans (N/1000 + 1)*1000 - N (N/1000 + 1)*1000 (N/1000 + 1) N/1000 N 1000 1 1000 N 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);

        Integer N = sc.nextInt();

        Integer ans = 0;
        if (N%1000 != 0) {// N が1000で割り切れないとき
            ans = (N/1000 + 1)*1000 - N;
        }

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

        Integer N = sc.nextInt();

        Integer ans = 0;
        if (N%1000 != 0) {// N が1000で割り切れないとき
            ans = (N/1000 + 1)*1000 - N;
        }

        System.out.println(ans);
    }
} Main

import java.util.Scanner;

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

        Integer N = sc.nextInt();

        Integer ans = 0;
        if (N%1000 != 0) {// N が1000で割り切れないとき
            ans = (N/1000 + 1)*1000 - N;
        }

        System.out.println(ans);
    }
}