Count working days

gistfile1.txt

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Numerics;
using System.Globalization;
using System.Text.RegularExpressions;

namespace Praktice
{
    class Program
    {
        static void Main(string[] args)
        {
            string startDate = Console.ReadLine();
            string endDate = Console.ReadLine();

            string format = "dd-MM-yyyy";
            CultureInfo provider = CultureInfo.InvariantCulture;
            DateTime start = DateTime.ParseExact(startDate, format, provider);
            DateTime end = DateTime.ParseExact(endDate, format, provider);
            List<string> hollydays = new List<string>() {"01-01","03-03","01-05","06-05","24-05","06-10", "22-10", "01-11","24-12","25-12","26-12" };                                                                   
            int count = 0;

            for (DateTime i = start; i <= end; i = i.AddDays(1.0))
            {
                string test = i.ToString();
                string dateToCheck = test.Substring(0, 2)+"-"+test.Substring(3,2);
                string a = i.DayOfWeek.ToString();
                if (!hollydays.Contains(dateToCheck))
                {
                    if ( a !="Saturday" && a != "Sunday")
                    {
                        count++;
                    }                   
                }
            }
            Console.WriteLine(count);          
        }
    }
}