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 java.math.BigDecimal
import java.util.*

fun main(args: Array<String>) {
    val sc = Scanner(System.`in`)
    val a = sc.nextDouble()
    val b = sc.nextDouble()
    println(problem169c(a, b))
}

fun problem169c(a: Double, b: Double): String {
    return BigDecimal(a).multiply(BigDecimal(b).multiply(100.toBigDecimal())).div(100.toBigDecimal()).toString().split(".")[0]
}