Identify Unique Values from 2 colums

Hello everyone,

I am struggling to come up with a formula to find every unique value between two different columns. I would want it to identify a unique number only if it is unique between the two columns i.e if there is a number that, when both columns were put together, still is only shown once it would be considered unique. It would not be considered unique if it is unique in one column but can be found in another column as well.

The ultimate goal is to identify these so I can delete them out and see the same numbers essentially in both columns. I can't do conditional formatting and filter because my data is 60,000+ rows long and it just won't work.

I am perfectly fine with some sort of helper column. Thanks!!!!

P.S. there is another forum I posted this on... https://www.mrexcel.com/board/thread.../#post-5434390

This is actually something that is exported from a program at work that has discrepancies between two "views". I am working to identify which (of those that contain the same ID) contain discrepancies in the "Y" or "N". Thanks!