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 __sub__(self, r):

        return Rational(self.p * r.q - self.q * r.p, self.q * r.q)

    def __mul__(self, r):

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

    def __div__(self, r):

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

    def __str__(self):

        g = gcd(self.p, self.q)

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

    __repr__ = __str__

r1 = Rational(1, 2)

r2 = Rational(1, 4)

print r1 + r2

print r1 - r2

print r1 * r2

print r1 / r2