using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        var regex = new Regex("^([a-zA-Z]):(.*)");

        var match = regex.Match("C:\\Hoge\\Fuga");

        for (var i = 0; i < match.Captures.Count; i++) {

            Console.WriteLine(match.Captures[i].Value);

        }

    }

}