Dari or Pashto

I might be going on a trip in a couple of months. To see an exotic place that I have only seen on the tele. My wife is "super" excited for me to go...I would like to learn a little more about the language before I go. Sooooo The question is which do I learn if I was to stay in a place like oh, I don't know,,,.Kabul for a year or so, Pashto or Dari.