Count Number of recurring character in a string

using System;

using System.Linq;

namespace ConsoleApplication1

{

    class Program

    {

        static void Main(string[] args)

        {

            string x = "aaaaanurAg";

            var z = x.ToUpper().ToCharArray().Where(y=>y=='A').Count();

            Console.WriteLine(z);

            Console.ReadLine();

        }

    }

}

Output: