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 Microsoft.VisualBasic.CompilerServices;
using System;
using System.Collections.Generic;
using System.ComponentModel.Design;
using System.Drawing;
using System.Dynamic;
using System.Globalization;
using System.IO.Compression;
using System.IO.Pipes;
using System.Linq;
using System.Numerics;
using System.Runtime.InteropServices.ComTypes;
using System.Text;
using static System.Console;
using static System.Math;

namespace AtCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            var AB = ReadDoubles();
            WriteLine(Floor(AB[0] * AB[1]));
        }
        private static string Read() { return ReadLine(); }
        private static string[] Reads() { return (Read().Split()); }
        private static int ReadInt() { return int.Parse(Read()); }
        private static long ReadLong() { return long.Parse(Read()); }
        private static double ReadDouble() { return double.Parse(Read()); }
        private static int[] ReadInts() { return Array.ConvertAll(Read().Split(), int.Parse); }
        private static long[] ReadLongs() { return Array.ConvertAll(Read().Split(), long.Parse); }
        private static double[] ReadDoubles() { return Array.ConvertAll(Read().Split(), double.Parse); }
    }
}