using System;

using System.Globalization;

​

namespace Csharp

{

    public class Program

    {

        public static void Main()

        {

            CultureInfo culturaBrasil = new CultureInfo("pt-BR");

            string diaSemana = culturaBrasil.DateTimeFormat.GetDayName(DayOfWeek.Sunday);

            Console.WriteLine(diaSemana);

        }       

    }

}