using System;

public class Program

{

    public static void Main()

    {

        double? num1 = null;

         double? num2 = 3.14157;

         double num3;

         num3 = num1 ?? 5.34;      

         Console.WriteLine(" Value of num3: {0}", num3);

         num3 = num2 ?? 5.34;

         Console.WriteLine(" Value of num3: {0}", num3);

         Console.ReadLine();

    }

}