using System;
using System.Linq;
using System.Text.RegularExpressions;
public class Test
{
	public static void Main()
	{
		var text = "(1 * (2 - 3)) + 4";
		var pattern = @"(?=(\((?>[^()]+|(?<c>)\(|(?<-c>)\))*(?(c)(?!))\)))";
		var results = Regex.Matches(text, pattern)
			.Cast<Match>()
			.Select(m => m.Groups[1].Value)
			.ToList();
		Console.WriteLine(String.Join(", ", results));
	}
}