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: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;

namespace ABC
{
    class ABC169C
    {
        const string FILE = @"..\..\data.txt";

        static void Main(string[] args)
        {
#if DEBUG
            Console.SetIn(new StreamReader(FILE));
#endif
            var line = Console.ReadLine();
            var sa = line.Split(' ');
            long a = long.Parse(sa[0]);
            string b = sa[1];
            var ba = b.Split('.');
            int b0 = int.Parse(ba[0]);

            char[] bpoint = ba[1].ToCharArray();


            int b1 = 0;
            int b2 = 0;
            if (bpoint.Length == 1)
            {
                b1 = int.Parse(bpoint[0].ToString());
            }
            if (bpoint.Length == 2)
            {
                b1 = int.Parse(bpoint[0].ToString());
                b2 = int.Parse(bpoint[1].ToString());
            }

//            long result = a * b0 + (a / 10) * b1 + (a / 100) * b2;
            long result = (a * b0 * 100) + (a * 10) * b1 + (a) * b2;
            result /= 100;
            Console.WriteLine(result);



#if DEBUG
            Console.WriteLine("end");
            Console.SetIn(Console.In);
            Console.ReadKey();
#endif
        }
    }
}