What will be the output of the following C# code?

class student
{
    int []scores = new int[5] {23, 42, 54, 11, 65};
    public int this[int index]
    {
        get
        {
            if (index < 5)
            return scores[index];
            else
            {
                Console.WriteLine("invalid index");
                return 0;
            }
        }
        set
        {
            if (index < 5)
            scores[index] = value;
            else
            Console.WriteLine("invalid index");
        }
    }
}
class Program
{
    public static void Main(string[] args)
    {
        student s = new student();
        Console.WriteLine(s[4] + 8);
        Console.ReadLine();
    }
}