import java.util.Scanner;

public class Main {
    long N;
    long M;
    long Dist;
    long Digit;
    long Divide;
    Scanner sc = new Scanner(System.in);
    public static void main(String[] args) {
        new Main().solve();
    }

    void solve() {
        N = sc.nextLong();
        M = sc.nextLong();
        Dist = N / M;
        Digit = (long)Math.log10(Dist) + 1;
        Divide = 1;
        for(int i = 0; i < Digit - 1; i ++) {
            Divide = Divide * 10;
        }
        Dist = (Dist / Divide) * Divide;
        if(Dist < 1000) {
            System.out.println(0);
        } else {
            while(Dist * M < N) {
                Dist = Dist + 1000;
            }
            System.out.println(Dist);
        }
    }
}