Problem:
Score : 300 points

Problem Statement

Compute A \times B, truncate its fractional part, and print the result as an integer.

Constraints

0 \leq A \leq 10^{15}

0 \leq B < 10

A is an integer.

B is a number with two digits after the decimal point.

Input

Input is given from Standard Input in the following format:

A B

Output

Print the answer as an integer.

Sample Input 1

198 1.10

Sample Output 1

217

We have 198 \times 1.10 = 217.8. After truncating the fractional part, we have the answer: 217.

Sample Input 2

1 0.01

Sample Output 2

0

Sample Input 3

1000000000000000 9.99

Sample Output 3

9990000000000000

Solution in Scala (2.13.1) (judge verdict: Wrong Answer)

import scala.io.StdIn._
import scala.math._

object Main extends App with StdInHelper {
  val ss = readStrings
  val a = ss(0).toLong
  val b = ss(1).toDouble
  println(floor(a / pow(10, 10).toLong * b).toLong * pow(10, 10).toLong)
}

trait StdInHelper {
  def readStrings = readLine.split(" ")
  def readInts = readLine.split(" ").map(_.toInt)
  def readLongs = readLine.split(" ").map(_.toLong)
  def readDoubles = readLine.split(" ").map(_.toDouble)
}