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

public class N350 {

	public static void main(String[] args)
	{
		Scanner sc=new Scanner(System.in);
		BigDecimal v=new BigDecimal(Double.toString(sc.nextDouble())),t=new BigDecimal(sc.nextInt());
		System.out.println(v.multiply(t).setScale(0, BigDecimal.ROUND_DOWN));
	}

}