// O(n)

using System;

using System.Collections;

public class Program

{

    public static void Main()

    {

        var exp = "[(])";

        var stack = new Stack();

        if(string.IsNullOrWhiteSpace(exp)){

        Console.WriteLine("not balanced");

        }

        foreach(char c in exp){

            if(c == '{' || c == '(' || c == '['){

                stack.Push(c);

            }

            else if(c =='}' || c == ')' || c == ']'){

                var prev = (char)stack.Pop();

                if(c == '}' && prev == '{') continue;

                if(c == ']' && prev == '[') continue;

                if(c == ')' && prev == '(') continue;

                else

                    break;

            }

        }

        if(stack.Count > 0){

        Console.WriteLine("not balanced");

        }

        else{

        Console.WriteLine("balanced");

        }

    }

}