4. Balanced Brackets

lines = len(input())
is_balanced = False
brackets = []

for index in range(0, lines):
    symbol = input()
    if symbol.isalnum():
        symbol = input()
    if symbol == "(":
        brackets.append(symbol)
    elif symbol == ")":
        brackets.append(symbol)

for index in range(len(brackets)):
    if brackets[index] == "(" and index % 2 == 0:
        is_balanced = True
    elif brackets[index] == ")" and index % 2 != 0 and is_balanced:
        is_balanced = True
    else:
        is_balanced = False
        break

if is_balanced:
    print("BALANCED")
else:
    print("UNBALANCED")