The ⁿ theorem for semisimple Hopf algebras

We give an algebraic version of a result of G. I. Kac, showing that a semisimple Hopf algebra A of dimension pn, where p is a prime and n > 0, over an algebraically closed field of characteristic 0 contains a non-trivial central group-like. As an application we prove that, if n = 2, A is isomorphic to a group algebra.