using System;

using System.Web;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        string s = " !@#$%^&*()_+-=[]{}:\";'<>,.>?/`~ День поля ВолгоградАгро - 2014 !@#$%^&*()_+-=[]{}:\";'<>,.>?/`~";

        string test2 = Regex.Replace(s, @"(?=[^a-z0-9\s-])((?!\p{IsCyrillic}).)", "");

        test2 = Regex.Replace(test2, @"\s+", " ").Trim(); // convert multiple spaces into one space  

        test2 = Regex.Replace(test2, @"\s", "-");

        Console.WriteLine(test2);

    }

}