using System;

public class Program

{

    public static void Main()

    {

          string s = "CEI 124";

            string pattern = @"(?<string>\D+)\s(?<number>\S*)";

​

            System.Text.RegularExpressions.Regex r = new System.Text.RegularExpressions.Regex(pattern);

​

            System.Text.RegularExpressions.Match m = r.Match(s);

            Console.WriteLine("*"+m.Groups["string"].Value+"*");

            Console.WriteLine("*"+m.Groups["number"].Value+"*");

    }

}