CPC vs CPC-P!! Help please!

Best answers
I have been going back and forth between the two & cant decide on the credential I want to pursue! I have experience in claims & referrals processing and have dealt with many functions except actually work in the providers office. I've always been on the payor side of physicians services. I recently completed my medical billing and coding program and have a degree in health services management. Eventually I want to open my own medical billing company so I'm looking for a credential that will complement that as well. Any advice on CPC or CPC-P is greatly appreciated!