URL rewrite to remove 2 folders

I hope you are doing well. I'm fairly new with IIS URL rewrite and I'm having trouble doing the below:

I have this URL, http://sub.domain.com/folder1/folder2

I want to use this URL Instead, http://sub.domain.com/f3

basically I want to replace folder1/folder2 with f3.

I have been trying to do so without success, would anyone be kind enough to help construct the IIS URL rewrite rule?

Thanks a lot for your time,

Michael