using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Text.RegularExpressions;

                    using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

        List<int> test = new List<int>();

        Parallel.For(1, 10000, (i) =>

                     {

                         test.Add(i);

                     });

​

        Console.WriteLine(test.Count);

    }

}