using System;

using System.Collections;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Greetings SpoiledTechie.com");

        /*if your spans are like string, you can convert them... with something like

        TimeSpan ts = TimeSpan.Parse(value);*/

        TimeSpan minSpan =  TimeSpan.Zero;

        TimeSpan maxSpan =  new TimeSpan(10,20, 0);

        List<Tuple<TimeSpan,TimeSpan>> availableIntervals = new List<Tuple<TimeSpan,TimeSpan>>();

        availableIntervals.Add(new Tuple<TimeSpan, TimeSpan>(new TimeSpan(2,30,0), new TimeSpan(3,43,0)));

        availableIntervals.Add(new Tuple<TimeSpan, TimeSpan>(new TimeSpan(4,25,0), new TimeSpan(4,59,0)));

        availableIntervals.Add(new Tuple<TimeSpan, TimeSpan>(new TimeSpan(7,21,0), new TimeSpan(9,25,0)));

        List<Tuple<TimeSpan,TimeSpan>> missingIntervals = ComputeMissingTimeSpans(availableIntervals,minSpan,maxSpan);

        foreach(var interval in missingIntervals)

        {

            Console.WriteLine(interval.Item1.ToString() + " - " + interval.Item2.ToString());

        }

    }

    private static List<Tuple<TimeSpan,TimeSpan>> ComputeMissingTimeSpans(List<Tuple<TimeSpan,TimeSpan>> availableIntervals, TimeSpan minSpan, TimeSpan maxSpan)

    {

        List<Tuple<TimeSpan,TimeSpan>> missingTime = new List<Tuple<TimeSpan,TimeSpan>>();

        if(availableIntervals.Count == 0)

        {

            missingTime.Add(new Tuple<TimeSpan, TimeSpan>(minSpan, maxSpan));

            return missingTime;

        }

        foreach(var interval in availableIntervals){

            if((interval.Item1 - minSpan).TotalSeconds > 1 ) 

            {

                missingTime.Add(new Tuple<TimeSpan, TimeSpan>(minSpan, interval.Item1.Add(TimeSpan.FromSeconds(-1))));

            }

            minSpan = interval.Item2.Add(TimeSpan.FromSeconds(1));

        }

        if((maxSpan - minSpan).TotalSeconds > 1)

            missingTime.Add(new Tuple<TimeSpan, TimeSpan>(minSpan, maxSpan));

        return missingTime;

    }       

}