Regex Formula not working

[BobbyQ]

I have two zip codes and one of them starts with a letter. I want to be able to match the one with a letter and assign a value. The formula I am using is as follows:
"IF REGEX_Match([Zip], "^[A-Z]$") then 2 else 1 ENDIF"

The two entries are as follows for Zip:

43416

M9W5P4

I was expecting a 1 for 43416 and a 2 for M9W5P4 but am instead getting a 1 for M9W5P4. Any help would be greatly appreciated. Thank you

[binuacs · Accepted solution]

@BobbyQ 

[BobbyQ]

Thank you!