using System;
using System.Text.RegularExpressions;

/*
http://k...content-available-to-author-only...s.com/2010/12/14/net-regex-mathcing-mixed-balanced-parentheses/
*/

public class Test
{
	public static void Main()
	{
		string pattern = @"
(
    [^(){}\[\]]+
    | \( (?=[^)]*  (?<Stack> \) ) )
    | \[ (?=[^\]]* (?<Stack> \] ) )
    | \{ (?=[^}]*  (?<Stack> \} ) )
    | \k<Stack> (?<-Stack>)
)+?
(?(Stack) (?!))
";
		string text = Console.ReadLine();
		MatchCollection matches = Regex.Matches(text, pattern,
                	RegexOptions.IgnorePatternWhitespace | RegexOptions.ExplicitCapture);
		foreach (Match match in matches)
            	{
             	   Console.WriteLine(match.Value);
		}
	}
}