package no350;

import java.math.RoundingMode;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		System.out.println(sc.nextBigDecimal().multiply(sc.nextBigDecimal()).setScale(0, RoundingMode.FLOOR).toPlainString());
	}

}