Surface Integrals, Stokes & Divergence · Easy problem

Let $\mathbf F = (x^2y,\ yz^3,\ xz^2)$ and let $S$ be the unit sphere $x^2 + y^2 + z^2 = 1$ with outward normal. Find $\iint_S (\nabla\times\mathbf F)\cdot d\mathbf S$.