please help! Thanks!

Use the Divergence Theorem to compute the net outward flux of the field F = ( - 4x, 3y, 6z) across the surface S, where S is the surface of the paraboloid z =4 -x -y , for z 2 0, plus its base in the xy-plane. The net outward flux across the surface is (Type an exact answer, using it as needed. )