Need help with formula:

We have a validation on the LinkedIn field that allows only in this format: 

https://www.linkedin.com/in/example...

Here is the formula currently in the validation:

NOT (REGEX( LinkedIn_Username__c, "^(http|https)://

www.linkedin.com/in/([a-zA-Z0-9_!@#$&()\\-.+]+)

")),

FALSE

Now we need to stripe out the validation of anything after 

linkedin.com/ 

I tried removing this part but it didn’t work:

in/([a-zA-Z0-9_!@#$&()

\\-.+]+)

Please help!

#Formula Help

#Salesforce Admin #Formulas #Validation Rule