So this is going to be two-thirds times x squared minus one to the two-thirds minus one, so to the negative one-third power, times the derivative of the inside with respect to x. So the derivative of x squared minus one with respect to x is two x. There's a fire hydrant. A fire, fire, fire, not a hydrant. That would be a noisy hydrant. There's a fire truck outside. But okay, I think it's passed.