04. Balanced Brackets

iterations = int(input())

opening_brackets = 0
closing_brackets = 0

for i in range(iterations):
    line = input()
    if line == "(":
        opening_brackets += 1
    elif line == ")":
        closing_brackets += 1
    if closing_brackets > opening_brackets:
        break
    if opening_brackets - closing_brackets > 1:
        break

if opening_brackets != closing_brackets:
    print("UNBALANCED")
else:
    print("BALANCED")