Is there a exponential law for categories?

Question

I wonder whether the following statement is true or not： Let $\mathcal C,\mathcal D,\mathcal E$ be categories, then the functor category $({\mathcal C}^{\mathcal D})^{\mathcal E}$ is equivalent to both $\mathcal C^{\mathcal D\times\mathcal E}$ and $({\mathcal C}^{\mathcal E})^{\mathcal D}$. I am afraid that it involves something in set theory which I cannot deal with so I ask for your help.