Problem with for loop, and trying to split up list declaration from list string-to-datetime conversion

Question

So I'm trying to make a 'PTO calculator' that will calculate the percentage of the year, in workdays, remaining vs the percentage of my PTO hours at work remaining. Basically, an application that I can use to quickly see if I'm burning my allotted paid time off too quickly for the entire year. Here's what I have so far,

using System;
using System.Globalization;
using System.Linq;
class Program
{
static void Main()
{
    int PTOHoursTotal = 144;
    int PTOleft = 91;//user inputs the number of PTO hours remaining
    int workdays = 366;//the for loop below will run through the entire year and deduct 
    //holidays and weekends from 366 to give the total number of workdays in the year 
    var Holidays = new[]
    {
        "February 17, 2020", "May 25, 2020",
        "July 3, 2020", "September 7, 2020",
        "October 12, 2020", "November 11, 2020",
        "November 26, 2020", "December 25, 2020"
    }.Select(str => DateTime.ParseExact(str, "MMMM d, yyyy", CultureInfo.InvariantCulture));
    for (DateTime i = DateTime(2020, 1, 1); i < (2020, 12, 31); i.AddDays(1))
    {
        if (Holidays.Contains(i) || i.DayOfWeek == Saturday || i.DayOfWeek == Sunday)
        {
            workdays--;
        }
        Console.WriteLine(workdays);
    }
}

I'm fairly certain there's something wrong with my for loop, and on top of that, if someone could show a way to split the declared list of holiday strings from the conversion of the strings to datetimes, that would be much appreciated. The final number of workdays should be something like 251 according to some date calculation website.