import java.util.Scanner;

public class yukicoder_128 {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		
		int n = scanner.nextInt();
		int m = scanner.nextInt();
		
		int a = n / m / 1000;
		int money = a * 1000;
		
		if (money < 1000) {
			money = 0;
		}
		
		System.out.println(money);
	}
}