using System;
using System.Linq;
using System.Numerics;

namespace apps
{

    class Program
    {


        static void Main()
        {
            // BALANCING

            int N = GetInt(); ;
            bool Unbalanced = false;

            string input = string.Empty;

            int Braket_Equality = 0;
            for(int i =0; i<N; i++)
            {
                input = Get();
                if (input == "(")
                {
                    if (Braket_Equality > 1) { Unbalanced = true; }  // mark as unbalanced if a bracket is not the right bracket
                    Braket_Equality++;
                }
                if (input == ")")
                {
                        if (Braket_Equality < -1) { Unbalanced = true; } // mark as unbalanced if a bracket is not the right bracket
                            Braket_Equality--;
                }

            }

            if (Unbalanced) { Console.WriteLine("UNBALANCED"); }
            else
            {

                if (Braket_Equality == 0) { Console.WriteLine("BALANCED"); }
                else
                {
                    Console.WriteLine("UNBALANCED");
                }
            }

        }
        //-----------------------------------------------------------------------------
        static int GetInt() { return int.Parse(Console.ReadLine()); }
        static string Get() { return Console.ReadLine(); }

    }
}