unlockcode for ddx512 kenwood stero/dvd/navigation stereo?

I had my kenwoodddx512 navigation radio installed in downtown I had my battery replaced recently and dont recall the gentleman giving me any code..that's the sys is requesting to be honest I don't know a damn thing about stereo or codes I'm a girl to top it off. If its not one thing its another can someone please direct me or let know what to do.?? Please thank u