Hey Jude
The song is well known for it's sing-a-long ending. Paul McCartney leads a large crowd in song, they are singing together. What they are singing is a simple melody with very simple lyrics over and over. This part of the song has just three words. First the sound "na" is repeated many times, and then come the words "hey Jude." In English, "na" has no meaning, it is just a sound to sing with your voice.