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

public class Test
{
	public static void Main()
	{
		var str = "((1+2)*(4+3))";
		var pattern = @"(?=(\((?>[^()]+|(?<o>)\(|(?<-o>)\))*(?(o)(?!)|)\)))"; 
    	var result = Regex.Matches(str, pattern)
    		.Cast<Match>()
    		.Select(x => x.Groups[1].Value);
       	Console.WriteLine(string.Join("\n", result));
	}
}