Get ID of parent category

I’m trying to get the parent ID of a category. I’ve searched around but the only things I can find on this get the top level parent ID not the direct parent of the current page ID.

I have 3 layers of category:

-cat 1
——-cat 2
————-cat 3

cat 3 is a child of cat 2, cat 2 is a child of cat 1.

If I’m currently on the cat 3 page how can I get the ID of the category directly above it? (cat 2)

Appreciate any help!