Show Product Count For Each Category In Vertical Menu Subcategory Tree


I'm using cs-cart version 4.6.2 and I want to have some modifications on subcategories vertical menu in the way that it shows active product count for each category.

I know there are add-ons for the vertical menu to show product number beside each category but I prefer not to use addons.

Is there a way to add some code to show product count for each category in vertical menu subcategories tree?