How many times can you apply to the same school?

If you are denied admission, you will need to wait until the next admissions cycle to reapply. This will give you time to evaluate and address the weak points of your application. You should aim for R1 in the next year's cycle in order to give yourself a better chance. R1 deadlines are usually within the October/November timeframe however you should begin working on your application as soon as possible. Finally, you should not merely resubmit the exact same application - there is a reason it was denied and it should be addressed.

Thanks much for your advice!

No problem.