How to identify/highlight reverse cell combination from a list

Hi All,

I'm trying to identify/highlight cell combination that are reversed from a list. In this example, in column A I have a list of first names, in B a list of last names. This is what the report I use would produce. In column C, I have to create the pairing of column A and B with the concatenate formula (First name and last name).

I would like to be able to identify/highlight in column C all the instances where the value is actually reversed (Last name and first name). This example relates to names only to make it easier to understand, however I will be working with numbers (4 digit number codes). Also, I'm not sure if using the concatenate formula is the best way to achieve this, so any suggestion is welcomed!

Thanks,

J