Adobe Experience Platform Data Collection - Edit Rule - Right Operand needs to be changed to exclude the very special URL

There is a rule, that is set up properly to exclude actions for URLs, that contain mysubstring.

This rule works fine - it doesn't run a javascript code if the URL contains a mysubstring substring.

However, I need to make an exclusion from that rule, if the URLs additionally contain myspecialsubstring substring.

As result, I need to modify Right Operand input (its current value is simply mysubstring ) with something new. What should I put into that field (probably regexp value) ?  Thank you.

P.S. This page https://experienceleague.adobe.com/docs/data-workbench/using/dataset/c-reg-exp.html?lang=en# didn't help me too much.