public static void Main()
Console.WriteLine("Enter a number of week");
int num = int.Parse(Console.ReadLine());
Console.WriteLine("It's sunday");
Console.WriteLine("It's monday");
Console.WriteLine("It's thursday");
Console.WriteLine("It's wednsday");
Console.WriteLine("It's thirsday");
Console.WriteLine("It's friday");
Console.WriteLine("It's saturday");
Console.WriteLine("It's not a number of week");