using System;
using System.Text.RegularExpressions;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string txt = "rgb(139, 0, 0) none repeat scroll 0% 0% / auto padding-box border-box";

            Regex r = new Regex("(rgb)+(\\(.*\\))");
            Match m = r.Match(txt);
            if (m.Success)
            {
                var word1 = m.Groups[1].ToString();
                var word2 = m.Groups[2].ToString();
                Console.Write(word1+ word2);
            }
            Console.ReadLine();
        }
    }
}