using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        List<DateTime> allowedDates = new List<DateTime>();

        List<DateTime> excludedDates = new List<DateTime>();

        Console.WriteLine("Excluded Dates");

        excludedDates.AddRange(DatesInRange(new DateTime(2018, 6, 4), new DateTime(2018, 6, 6)));

        excludedDates.AddRange(DatesInRange(new DateTime(2018, 6, 11), new DateTime(2018, 6, 14)));

        excludedDates.AddRange(DatesInRange(new DateTime(2018, 6, 17), new DateTime(2018, 6, 20)));

        DateTime startDate = new DateTime(2018, 6, 1);

        DateTime checkDate = startDate;

        while(checkDate.Month == startDate.Month) 

        {

            if(!excludedDates.Any(ed => ed == checkDate))

            {

                allowedDates.Add(checkDate);

            }

            checkDate = checkDate.AddDays(1);

        }

        Console.WriteLine("Allowed Dates");

        allowedDates.ForEach(ad => Console.WriteLine(ad));

    }

    static List<DateTime> DatesInRange (DateTime startDate, DateTime endDate)

    {

        List<DateTime> datesInRange = new List<DateTime>();

        DateTime checkDate = startDate;

        while(endDate.Day >= checkDate.Day) 

        {

            datesInRange.Add(checkDate);

            Console.WriteLine(checkDate.ToString());

            checkDate = checkDate.AddDays(1);

        }

        return datesInRange;

    }

}