Solved How to check inventory if has 2 empty slots?

[Barbarx]

As title of thread telling: how to check inventory if has 2 empty slots? My english is so bad so i think you will know what i want to tell.
I tried something like this:

if player's inventory contains 2 air:

in inventory click.
SOLVED
if player has enough space for 2 stone:

 

[Deleted member 5254]

not stone, use something like "space for 2 shulker" or another non stackable item. 2 stones would take only one slot, right?