public static void Main()
DateTimeOffset firstDate = DateTime.Parse("2018-12-31");
DateTimeOffset secondDate = DateTime.Parse("2019-12-31");
difference = (firstDate - secondDate).TotalDays + 1;
Console.WriteLine(firstDate + " - " + secondDate + " - " + difference + " days, ");
Console.WriteLine((int)Math.Ceiling(difference / 7));