C# lock

 class Program
    {

        readonly static object _Sync = new object();
        const int _Total = 10;
        static long _Count = 0;

        static void Main(string[] args)
        {
            Task task = Task.Run(() => Decrement());

            for (int i = 0; i < _Total; i++)
            {

                lock (_Sync)
                {
                    _Count++;

                    Console.WriteLine($"in mian:{_Count}");
                }

            }

            task.Wait();
            Console.WriteLine(_Count);
            Console.ReadLine();
        }


        static void Decrement()
        { 
            for(int i = 0;i<_Total;i++)
            {
                lock (_Sync)
                {
                    _Count--;
                    Console.WriteLine($"in thread:{_Count}");
                }
          

            }
        }

    }