You will be given a definition of a task first, then some input of the task.
This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: Interstate 10, which runs southeast to northwest through town, connects Tucson to Phoenix to the northwest on the way to its western terminus in Santa Monica, California, and to Las Cruces, New Mexico and El Paso, Texas toward its eastern terminus in Jacksonville, Florida. I-19 runs south from Tucson toward Nogales and the U.S.-Mexico border. I-19 is the only Interstate highway that uses "kilometer posts" instead of "mileposts", although the speed limits are marked in miles per hour instead of kilometers per hour. Question: Which direction does I-19 run from Tucson?
Output:
south