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 Kotlin (1.3.71) (judge verdict: Wrong Answer)

import kotlin.math.*
import java.io.BufferedReader
import java.io.InputStreamReader
import java.util.*


private var fs = BufferedReader(InputStreamReader(System.`in`))
private fun readLn() = fs.readLine()!! // string line
private fun readStrings() = readLn().split(" ") // list of strings
private fun readLong() = readLn().toLong()
private fun readLongs() = readStrings().map { it.toLong() } // list of ints
private fun readInt() = readLn().toInt() // single int
private fun readInts() = readStrings().map { it.toInt() } // list of ints

fun main() {
    solveAtc()
}
fun solveAtc() {
    var input = Scanner(System.`in`)
    input.useLocale(Locale.US)
    var a = input.nextLong()
    var b = input.nextDouble()
    var c = b.toLong()

    println((((((b-c)*100)*a)/100L) + c*a).toLong())
}