import java.util.Arrays;
import java.util.LinkedList;
import java.util.Scanner;

public class Main {
	
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		final long N = sc.nextLong();
		final long M = sc.nextLong();
		
		System.out.println(((N / M) / 1000) * 1000);
		
	}
	
}