beast mode question

Hello everyone,

I'm having an issue trying to get this beast mode calculation validated.

We have tickets that is suppose to be updated but we want to track tickets that are not updated within 4 hrs.

And we want a color change when ticket is about to breach 4hrs with no update.

I wrote this but getting syntex error.

if DATE-(`Last_Update`)>=4 `Hours`then 1 else 0

I removed hours and replaced with '' but not getting any data.

Any assistance is greatly appreciated.