import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Tester2 {
	public static void main(String[] args) {
		try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
			long min = 1000;
			long M = Long.parseLong(br.readLine());
			long N = Long.parseLong(br.readLine());
			long a = M / min;
			a /= N;
			a *= min;
			System.out.println(a);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}