What is the music played at the start of the end credits on the the simpsons (s23e9)?

Im talking about the simpson season 23 episode 9 - Back to the Funny Future

I want to know the song played at the start of end credits .. that goes something like ta nana ta nana ta nana..What is the music played at the start of the end credits on the the simpsons (s23e9)?
It's called "Carol of the Bells"



http://www.youtube.com/watch?v=1TFrO8c_k鈥?/a>