Exam July Evening 1. Electricity

using System;
using System.Globalization;
using System.Threading;

public class Electricity
{
    public static void Main()
    {
        Thread.CurrentThread.CurrentCulture = CultureInfo.InvariantCulture;
        checked
        {
            int floors = int.Parse(Console.ReadLine());
            int flats = int.Parse(Console.ReadLine());
            string givenTime = Console.ReadLine();

            string hourStr = givenTime.Remove(givenTime.IndexOf(':'));
            int givenHour = int.Parse(hourStr);

            int totalFlats = floors * flats;
            double powerLamp = 100.53;
            double powerComputer = 125.90;
            double totalPower = 0;
            if (givenHour >= 14 && givenHour <= 18)
            {
                totalPower = totalFlats * ((2 * powerLamp) + (2 * powerComputer));
            }
            else if (givenHour >= 19 && givenHour <= 23)
            {
                totalPower = totalFlats * ((7 * powerLamp) + (6 * powerComputer));
            }
            else if (givenHour >= 0 && givenHour <= 8)
            {
                totalPower = totalFlats * (powerLamp + (8 * powerComputer));
            }
            else if (givenHour >= 9 && givenHour <= 13)
            {
                totalPower = 0;
            }

            Console.WriteLine("{0} Watts", (int)totalPower);
        }
    }
}