What is the notation for the max element over two 2D matricies (images)

Question

I have two images which contain scalar values, let's call them $X$ and $Y$. They are each of size $h \times w$. How do I compactly write the maximum scalar of the two matrices?

My initial thought is the following:

$\max\limits_{ i,j,k,l} ( \mathbf{X}_{ijkl} \vert \mathbf{Y}_{kl})$

Answer 1

$$\max\left(\max_{i,j} X_{i,j}, \max_{i,j} Y_{i,j}\right)$$