Instructions: Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
Input: Context: Mad Vallis is a valley in the Hellas quadrangle of Mars, with its location centered at 56.5 S and 283.9 W. It is 524 km long and was named after the Mad River in Vermont, USA.
Question: On what moon or planet can Mad Vallis be found?
Output:
mars