Restriction of element character in patten mapping

Hi All,

I written a pattern as below to capture E-1422 A, but with these other elements appearing in indexing gateway.

e.g. E-1405 Shellside coming as E-1405 S

<!-- E-1422 A -->
<Pattern from="\d{0}[A-Z]{1}-\d{4}\s[A-Z]" to="Unknown"/>

how to restrict these

tried

<!-- E-1422 A -->
<Pattern from="^\d{0}[A-Z]{1}-\d{4}\s[A-Z]$" to="Unknown"/>

it is not working.

please help.