using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var list = new List<string>();

        list.Add("a");

        list.Add("b");

        list.Add("c");

        var filtered = list.Where(el => el == "z");

        var count = filtered.Count();

        Console.WriteLine(count);

​

    }

}