Surface Integrals, Stokes & Divergence · Easy problem

The surface $z = x^2 + y^2$ is parametrized by $\mathbf r(u, v) = (u, v, u^2 + v^2)$. Find $|\mathbf r_u \times \mathbf r_v|$ at the point where $u = 1$, $v = 1$.