Hi Everyone

I need to create a custom data validation rule for an entire column to allow
the following data types only:

1. numbers greater than 0
2. Specific Letters: "c", "C', "N", and "n".

So Far I've come up with this formula:

=OR(AND(ISNUMBER(E5),E5>0),EXACT(E5,"n"),EXACT(E5,"N"),EXACT(E5,"C"),EXACT(E5,"c"))

However, I cannot use the "apply these changes to all other shells with the
same settings" option because I'm using the "EXACT" feature.

I would greatly appreciate any help at all...

Thank you in advance for any suggestions, Antonio