TimeOfExam_StartUpTime

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

namespace TimeOfExam
{
    class Program
    {
        static void Main(string[] args)

        {
            Console.Write("Exam start at: ");
            Console.WriteLine(DateTime.Now.ToString("HH:mm:ss"));
                //Console.WriteLine("Enter FIRST time: for example:hour: min:sec 15:25:10");
                //DateTime firstTime = DateTime.Now.ToString("h:mm:ss tt");
DateTime firstTime = new DateTime();
            firstTime = DateTime.Parse(DateTime.Now.ToString("h:mm:ss tt"));
            //firstTime = DateTime.Parse(Console.ReadLine());

            Console.WriteLine("Enter LAST time: for example:hour:  min:sec 15:25:10");
            DateTime secondTime = new DateTime();
            secondTime = DateTime.Parse(Console.ReadLine());


            if (secondTime < firstTime)
            {
                TimeSpan difference = (firstTime - secondTime);
                difference -= TimeSpan.FromHours(24);
                difference = difference.Duration();
                Console.WriteLine("Time of Exam: {0}", difference);


            }
            else if (secondTime > firstTime)
            {
                TimeSpan difference = (secondTime - firstTime);
                Console.WriteLine("Time of Exam: {0}", difference);

            }
            Console.ReadLine();

        }

    }
}