Compute the surface integral over the given oriented surface:

$\mathbf{F}=\left< 0,0,e^{y+z}\right> \text{,}\quad$ boundary of the cube $0\le x, y, z\le 3 \text{,} \quad$ outward-pointing normal

$\iint_S \mathbf{F} \cdot d\mathbf{S} =$