A cubic box of side a = 0.320 m is placed so that its edges are parallel to the coordinate axes, as shown in the figure. There is NO net electric charge inside the box, but the space in and around the box is filled with a nonuniform electric field of the following form: E(x,y,z) = Kz j + Ky k, where K = 4.50 N/(Cm) is a constant. What is the electric flux through the top face of the box?