AdSense and Yardbarker Ad Network

I have a question about Google Adsense and Yardbarker Ads. I run both on my site. Does anyone know if I use a skyscraper from each (YB top right/Google mid-left) if this is a TOS violation? I am starting to make some good money from Google so the last thing that I'd want to do is get a TOS violation and lose it.

Any help on this would greatly be appreciated.

Thanks everyone

 

https://www.google.com/adsense/support/bin/answer.py?hl=en&answer=32849