using System;

using System.Threading;

​

public class LockStatement 

{ 

    public static void Main()

    {

        var mutex = new Mutex();

        int n = 0;

        var up = new Thread(() =>

        {

            for (int i = 0; i < 10000; i++)

            {

                mutex.WaitOne();

                n++;

                mutex.ReleaseMutex();

            }

        });

        up.Start();

        for (int i = 0; i < 10000; i++)

        {

            mutex.WaitOne();

            n--;

            mutex.ReleaseMutex();

        }

        up.Join();

        Console.WriteLine(n);

    }

}