Decreasing a number field by '1' in one list if an item is added to a different list

[Anonymous]

Hi. I have two lists. One is an Inventory List the other is a Stock Issued list. A user picks a stock item by using a unique InventoryID number to identify the stock and what I need to happen is that when an item is added to the Stock Issued list that number field called Quantity reduces by '1' in the Inventory list. I'm just coming back to Power Automate and was thinking of using a Condition would compare the InventoryIDs and then using an expression in a compose function to reduce the number. Any guidance on how to configure these would be welcome.

Thanks