using System;

​

public class Program

{

    public static void Main()

    {

        string fuse = "4  x  57x2   x ax       4";

        if (fuse != null)

        {

            var list = fuse.Split('x');

            int calc = 1;

            foreach (string n in list)

            {

                int testRes = 0;

                if (Int32.TryParse(n, out testRes))

                {

                    if (testRes != 0)

                    {

                        calc = calc * Int32.Parse(n);

                    }

                }

            }

​

            Console.WriteLine(calc);

        }

    }

}