# Fraction - Initial skecth to be competed
#
# Author:  Yotam Medini  yotam.medini@gmail.com -- Created: 2006/September/29
#


def str2nd(s):
    "Given string of the form  'nnnn/dddd'  return (nnnn, dddd) or None"
    ....



class Fraction:

    def __init__(self, n=0, d=1):
        self.n = n
        self.d = d


    def __str__(self):
        return "(%d/%d)" % (self.n, self.d)


    def strset(self, s):
        ok = True
        nd = str2nd(s)
        if nd == None:
            pass
            # .....  
        else:
            self.n = ....
            self.d = ....
        return ok

    def __add__(self, other):
        ...

    def __mult__(self, other):
        ...


if __name__ == '__main__':  # Test program
    import sys
    
    x1 = Fraction()
    x2 = Fraction()
    s1 = sys.argv[1]
    s2 = sys.argv[2]
    x1.strset(s1)
    x2.strset(s2)
    sys.stdout.write("x1+x2 = %s + %s = %s\n" % (x1, x2, x1 + x2))
    sys.exit(0)