import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong();
		long b = sc.nextLong();

		a = a / 1000;
		if(a < b){
			System.out.println("0");
		}else{
			System.out.println(a/b*1000);
		}
	}
}