This is because in Python 3.X map returns an iterator instead a list. In general iterators in Python are "empty" after first runthrough thus min(n) tries to run on empty iterator (emptied by max) and throws an error.
Solution: use list(map(...)).

Python 3 is, in many ways, not backward compatible with Python 2. But, this kata is for Python 2.

Looks like this solution is working only for Python 2.7.6. In 3.4.3 I'm getting error: ValueError: min() arg is an empty sequence