I'm just going to reevaluate it here to the right of her work. So let's see, f prime of x is just going to be the chain rule. I'm going to take the derivative of the outside with respect to the inside. 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.