Serial number for reinstalling Lightroom V4

I have reinstalled Lightroom V4 on my new laptop.  I have managed to find a download for the software, and it appears to have successfully worked but I'm not sure how I find my serial number to register the programme.  I can see the registered product sitting in my adobe account but the only number there is a 24 digit number (needs a 6 digit).  Any suggestions where I can find my serial number?

Thanks