Compare 2 Columns of Email Addresses to Find Duplicates?

Hello all! What I am trying a accomplish is to compare two columns of email addresses to find the duplicates. Then, I need to be able to sort or somehow organize the identified duplicates. There are 2,369 addresses in column A, and 5,360 in column B.

I have tried a number of formulas found online, but nothing seems to work. I'm a novice at Excel functions and would greatly appreciate help with this.

Thank you!
Laura