# L-14 MCS 275 Fri 12 Feb 2010 : substitute.py

def subs(s,x,y):
   """
   Replaces all occurrences of x
   in the string s by y.
   """
   L = s.split(x)
   return y.join(L)

def main():
   """
   Prompts user for string and two symbols.
   """
   s = raw_input("Give a string : ")
   x = raw_input("   what to replace : ")
   y = raw_input("replacement string : ")
   r = subs(s,x,y)
   print "the new string \"%s\"" % r

main()