How to show all first sunday in grid from the range of two date

 using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;

namespace WindowsFormsApplication3
{
    static class Program
    {
        /// 

        /// The main entry point for the application.
        /// 

        [STAThread]
        static void Main()
        {
            DateTime dt1 = new DateTime(2009, 10, 17);
            DateTime dt2 = new DateTime(2010, 10, 17);

            TimeSpan span = dt2 - dt1;
            Console.WriteLine
                     ("There're {0} days between {1} and {2}",
                     span.TotalDays, dt1.ToString(), dt2.ToString());

            int day = 0;
            for (int i = 0; i < span.TotalDays; i++)
            {
                if (dt1.Day % 7 != 0)
                {
                   day = ((int)(dt1.Day / 7))+1;
                }
                else
                {
                   day = ((int)(dt1.Day / 7));
                }
                if (dt1.DayOfWeek == DayOfWeek.Sunday &&  day==1)
                {
                    Console.WriteLine(dt1.Date.ToString("dd/MM/yyyy"));
                }
                dt1 = dt1.AddDays(1);
            }

            Console.ReadLine();
        }
    }
}