Chef and Bitwise Product

Chef got interested in bits and wanted to learn about them, so his friend Pintu gave him a special function $F(X,Y,Z) = (X \wedge Z) \cdot (Y \wedge Z)$, where $\wedge$ is the [bitwise AND](https://en.wikipedia.org/wiki/Bitwise_operation#AND) operator and $X, Y, Z$ are non-negative integers. Pintu wants Chef to maximise the function $F(X,Y,Z)$ for given $X$ and $Y$ by choosing an appropriate $Z