using System;

class BalancedBrackets
{
    static void Main(string[] args)
    {
        int n = int.Parse(Console.ReadLine());
        int opening = 0;
        int closing = 0;
        for (int i = 0; closing <= opening && i < n; i++)
        {
            string line = Console.ReadLine();
            if (line == "(")
            {
                opening++;
            }
            else if (line == ")")
            {
                closing++;
            }
        }
        Console.WriteLine(opening == closing ? "BALANCED" : "UNBALANCED");
    }
}