Remove Sub-Categories from the Category list

hey there guys,
I’m looking for a fast and easy way to remove the subcategories from the category listing. here’s what happens at the moment:
when I add for example Cars for the parent category and let’s say Audi as a sub category, both categories will show up in the main listing. I’m looking for a way to hide each subcategory and make the main categories be visible only.
the sub categories are visible on the category listing page, so if someone wants to narrow the results, they can easily click on a sub category above the posts. any idea on this one?

i’m using a plugin called Advanced Category Excluder, however it requires to hide every sub category one by one…this is ok if there are only a few sub categories, but will be a bad pain after adding like 50-150 sub-categories..

kind regards,
zerovic