How do I validate an entry on my form?

How do I validate an entry on my form?

I am fairly ignorant at deluge scripting or any coding for that matter; however, if someone would help me get the correct syntax for my field, I would be very grateful.  The field is called Your_Company_Code.  I want to be able to limit the entries in this field to values that I specify in the formula.  In the formula below, these values are "OK0609" and "AU1325".  Unfortunately, when I tried out my form, it did not allow any value at all.  What should my formula look like?

((input.Your_Company_Code  !=  "OK0609")  ||  (input.Your_Company_Code  !=  "AU1325"))

Thanks!