IMail - Rule to filter messages with no Subject

Question/Problem: I'm getting messages with no subject. How can I delete these messages?

The first rule will look for messages that do not have the 'Subject' header field.

Header does not contain subject\: (\w|\S) then filter the message.

Here is how this rule would be written in the rules file (rules.ima):
H!~subject\: (\w|\S):junk

The second rule will look for messages that have a blank Subject header.

Subject does not contain (\w|\S) then filter the message.

Here is how this rule would be written in the rules file (rules.ima):
S!~(\w|\S):junk

Note that the \w and \S parameters are case sensitive.