# How can I draw the this surface using Matlab?

I want to draw this surface on $[0,1]^3$:
$z=x$ for $x\geq y$ and $z=y$ for $y>x$
I know "meshgrid" coupled with "surface" command allows you to draw $z=x$ and $z=y$, respectively. But I have no idea how to account for the inequalities.