Balanced brackets

n = int(input())
found_open = False
balanced = True

for i in range(n):
  symbol_ = input()
  if symbol_ == '(':
    if not found_open:
      found_open = True
    else:
      balanced = False
  if symbol_ == ')':
    if found_open:
      found_open = False
    else:
      balanced =  False


if not found_open and balanced:
  print('BALANCED')
else:
  print('UNBALANCED')