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 C# (.NET Core 3.1.201) (judge verdict: Wrong Answer)

using System;

class Class2
{
    static void Main(string[] args)
    {
        string[] input = Console.ReadLine().Split(' ');
        ulong A = ulong.Parse(input[0]);
        double B = double.Parse(input[1]);

        ulong BB = (ulong)(B * 100);

        ulong calc = (A * BB) /100;



        Console.WriteLine(calc.ToString());
    }
}