import java.math.BigDecimal;
import java.util.Scanner;

public class Main {

	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);

		BigDecimal v = new BigDecimal(sc.next());
		BigDecimal t = new BigDecimal(sc.next());

		System.out.println(solve(v, t));

		sc.close();
	}

	public static int solve (BigDecimal v, BigDecimal t) {
		return v.multiply(t).intValue();
	}

}