HOW TO CHECK THE AMOUNT OF AN ITEM USING A SCRIPT?

Basically I want a skill to be usable if I have certain amount of an item, like bullets for example. If I don't have enough bullet "items", I can't use the shoot "skill". I really want to know what the specific call is to get an item amount?

What I've tried is (using Yanfly Skillcore):



What this is trying to do is if I don't have enough of the item in my inventory, the skill I want to use (this code is pasted in the skill's notes section which can be called) is hidden and can't be used, being the itemID number I want to check. This didn't work, of course.

edit: sorry the code i posted didnt show correctly so i just put a screenshot