#!/usr/local/bin/python3
#!/usr/bin/python
class FlipFlop:
  def __init__(self, v=False):
    self.x = not bool(v)
  def __nonzero__(self):
    self.x = not self.x
    return self.x

fl = FlipFlop()
print bool(fl)
print bool(fl)
print bool(fl)
print bool(fl)
print fl