Cannot find serial number on Photoshop Elements 13 box?

I purchased Adobe Photoshop Elements 13 from Amazon, received the box, but cannot find a serial code.
There was no insert in the box, it's not on the DVD sleeve, and the Adobe sticker on the back of the box was covered by another barcode sticker.  When I tried to carefully remove the top sticker it tore the lower one and now I cannot read that either.  What do I do?