U5 Unlimited text to Smart and Talk N Text valid for 1 hour

This offer from smart and talk n text unlimited text and valid for 1 hour is working until now and open to subscribe.
I'm using this from now, im searching to how to register U5 and now i get it how to register. To register just text U5 and send to 4545 and the smart will reply that you are registered in their service and you can star to use your unlimited text valid for 1 hour only.

To register U5:

- Text U5 to 4545 (1 hour Unlimited text to Smart and Talk N Text Subscribers)

Note: Do not input the space between the U5.