class?Rational(object):

????def?__init__(self,?p,?q):

????????self.p?=?p

????????self.q?=?q

????def?__add__(self,?r):

????????return?Rational(self.p?*?r.q?+?self.q?*?r.p,?self.q?*?r.q)

????def?__str__(self):

????????return?'%s/%s'?%?(self.p,?self.q)

????__repr__?=?__str__