With Y'PbPr, Y is for luminance, Pb is the difference between blue and Y, and Pr is the difference between red and Y.
With Y'CbCr, Y is for luma, Cb and Cr are blue and red chroma, respectively.
Many TVs have these things labeled Y Pb/Cb Pr/Cr. I'm surprised yours are seperate. It will probably work on either input.
You're fine where you're at. Enjoy it!