using System;

using FluentDateTime;

​

public class Program

{

    public static void Main()

    {

        DateTime productionDateTimeStamp;

        if (DateTime.TryParse("2023-01-08", out productionDateTimeStamp))

        {

            DateTime expiryDate = productionDateTimeStamp.AddDays(1).Previous(DayOfWeek.Sunday);          

            Console.WriteLine(expiryDate.DayOfYear.ToString());

        }

    }

}