Madonna - Don T Tell Me Acoustic Chords

I have only been playing the guitar for a month, so if I have made a mistake, take it easy.
This song was played live on David Letterman. I was able to figure out the chords by watching her play.
It's actually a pretty good song.

The only problem I'm still having is figuring out the rhythm. It's not too hard.

The chords are:

 C, G, D, Am

Thats basically the whole song. Just repeat those chords