using System;

using System.Collections.Generic;

using System.Text.RegularExpressions;

using System.Linq;

public class Program

{

    public static void Main()

    {

        string str = "v5.6.8_beta2";

        string pattern = @"^[vV](\d+)\.(\d+)\.(\d+)_?\w+(\d+)";

        MatchCollection matches = Regex.Matches(str, pattern);

        var groups = matches.First().Groups;

        foreach(var g in groups)

        {

            Console.WriteLine(g);

        }

    }

}