using System;
using System.Globalization;
public class Test
{
	public static int GetWeekNumber(DateTime dtPassed)
	{
	        CultureInfo ciCurr = CultureInfo.CurrentCulture;
	        int weekNum = ciCurr.Calendar.GetWeekOfYear(dtPassed, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
	        return weekNum;
	}
	public static void Main()
	{
		DateTime FirstDayOfTheYear = new DateTime(2026,1,1);
		Console.WriteLine(GetWeekNumber(FirstDayOfTheYear));
		Console.WriteLine(FirstDayOfTheYear.DayOfWeek);
	}
}
 

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