Surface Integrals, Stokes & Divergence · Medium problem

Let $S$ be the cap of the sphere $x^2 + y^2 + z^2 = 25$ with $z \ge 3$, oriented with upward (outward) normal, and let $\mathbf F = (-2y,\ 2x,\ xz)$. Use Stokes' theorem to find $\iint_S (\nabla\times\mathbf F)\cdot d\mathbf S$. Give an exact answer in terms of $\pi$.