Reinstall of Acrobat Pro X

I have been using Acrobat Pro X for a while now on my Mac. I had to do an erase/reinstall of my operating system, so after the reinstall I tried to copy my Acrobat Pro application back on to my hard drive, but that doesn't work. When I try to open Acrobat Pro it says I have to uninstall/reinstall it. I've done the uninstall and have my product serial number to do the reinstall, but I don't know how to get a download of the application itself without paying for another license. How do I do this?