#include <iostream>
#include <bits/stdc++.h> 
using namespace std;
 
bool isbracketbalanced( string expr )
{
	stack<char> s;
	char x;
 
	for( int i = 0; i < expr.length() ; i++ )
	{
		if( expr[i] == '(' || expr[i] == '[' || expr[i] == '{' )
		{
			s.push(expr[i]);
			continue;
		}
 
		if(s.empty())
		{
			return false;
		}
 
		switch( expr[i] )
		{
			case ')':
 
				x = s.top();
				if( x == '(' )
					s.pop();
				else
					return false;
				break;
 
			case '}':
 
				x = s.top();
				if( x == '{')
					s.pop();
				else
					return false;
				break;
 
			case ']':
 
				x = s.top();
				if( x == '[' )
					s.pop();
				else
					return false;
				break;
		}
 
	}
 
	if(s.empty())
	{
		return true;
	}
	else
	{
		return false;
	}
}
 
int main() {
	// your code goes here
	string test1 = "({[]})";
	string test2 = "({[]}])";
	string test3 = "({[]}))";
 
	if(isbracketbalanced(test3))
		cout << "bracket balanced";
	else
		cout << "bracket not balanced";		
	return 0;
}