RageQuit - Regex

using System;
using System.Linq;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using System.Text;

public class Program
{
	public static void Main()
	{
		string input = Console.ReadLine().ToUpper();

		StringBuilder result = new StringBuilder();

		string pattern = @"((?<letters>[\D]+)(?<num>\d+))";

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

		foreach (Match match in matches)
		{
			string letters = match.Groups["letters"].Value;
			int num = int.Parse(match.Groups["num"].Value);

			for (int i=0; i<num; i++)
			{
				result.Append(letters);
			}
		}

		int symbols = result.ToString().Distinct().Count();

		Console.WriteLine("Unique symbols used: {0}",symbols);
		Console.WriteLine(result.ToString());
	}
}