using System;

using System.Collections.Generic;

using System.Linq;

using ExtensionMethods;

​

public class Program

{

    public static void Main()

    {

        LinkedList<Day> Days = new LinkedList<Day>();

​

        Day day1 = new Day() { sunUp = 800, sunDown = 1800 };

        Day day2 = new Day() { sunUp = 755, sunDown = 1805 };

        Day day3 = new Day() { sunUp = 750, sunDown = 1810 };

        Day day4 = new Day() { sunUp = 745, sunDown = 1815 };

        Day day5 = new Day() { sunUp = 740, sunDown = 1820 };

​

        Days.AddLast(day1);

        Days.AddLast(day2);

        Days.AddLast(day3);

        Days.AddLast(day4);

        Days.AddLast(day5);

        int totalDays = Days.Count;

        int averageMinutes = Days.Sum(day => day.sunDown.ToMinutes() - day.sunUp.ToMinutes()) / totalDays;

        Console.WriteLine("There is an average of {0} minutes of night over the past {1} days.", averageMinutes, totalDays);

    }

    public class Day

    {

        public int sunUp { get; set; }

        public int sunDown  { get ; set; }

    }

}

​

namespace ExtensionMethods

{

    public static class IntExtensions

     {

        public static int ToMinutes(this int time)

        {

            return time / 100 * 60 + time - time / 100 * 100;

        }

    }

}