Calculate $\iint_R (x+y)^2 e^{x-y}dx dy$ on the given region

Calculate the integral
\[\iint_R (x+y)^2 e^{x-y}dx dy, ? R ? (x+y) 2 e x?y dxdy, \]
where $R$ is the region bounded by $x+y=1$, $x+y=4$, $x-y=-1$ and $x-y=1$.

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