Setting up a Destination Goal in Google Analytics using Regex

I want to set up a destination goal in GA to determine when a user reaches the end of a flow, or basically has completed a process.

The problem, the URL changes depending on the activity of the user so we have a URL like this (below) which can vary.


The S2 represents the last stage in the flow, which is the page I’m trying to capture. However the e1 could be any number depending on the other activities of the user.

Can someone help with writing a Regex to make sure GA captures the every time a user reaches the last page regardless of the execution number? Is there a way to ignore the “E1” value and simply match the rest? I am completely new to this part so I’d be embarrassed to share what I’ve tried 🙂