XeF_4 reacts with SbF_5 to form [ XeFm ]^n+[ SbF_y]^z-. m+n+y+z= ____

$\displaystyle \mathrm{XeF}_4$ reacts with $\displaystyle \mathrm{SbF}_5$ to form $$\begin{aligned} & {[\mathrm{XeFm}]^{n+}\left[\mathrm{SbF}_y\right]^{z-} .} \\ & m+n+y+z= \end{aligned} $$ $\displaystyle \_\_\_\_$