using System;

public class Program

{

    public static void Main()

    {

         DateTime day = new DateTime(2021, 8, 15);

        DateTime newday = DateTime.Now;

        Console.WriteLine($"day of week new {newday.DayOfWeek.ToString()}");

        Console.WriteLine($"day of week {day.DayOfWeek.ToString()}");

         DateTime endDay;

                if (day.DayOfWeek.ToString() == "Sunday")

                {

                    endDay = DateTime.Now.AddDays(-8);

                }

                else

                {

                    endDay = DateTime.Now.AddDays(DayOfWeek.Sunday - DateTime.Now.DayOfWeek);

                }

                string endOfPreviousWeek = endDay.ToString("M/d/yyyy");

                string statrOfPreviousWeek = endDay.AddDays(-6).ToString("M/d/yyyy");

                Console.WriteLine($"Date From {statrOfPreviousWeek}");

                Console.WriteLine($"Date To {endOfPreviousWeek}");

    }

}