05. Balanced Brackets

lines_input = int(input())
open_bracket = 0
closed_bracket = 0
flag = False

for i in range(1, lines_input + 1):
    symbol_input = input()
    if symbol_input == '(' and not flag:
        open_bracket += 1
        flag = True
    elif symbol_input == ')' and flag:
        closed_bracket += 1
        flag = False
if open_bracket == closed_bracket and open_bracket > 0:
    print('BALANCED')
else:
    print('UNBALANCED')