from erasure import erasure_source, erasure, retain
@erasure_source
def inputFromUser():
  x=raw_input()
  return x

@retain
def transform(st):
  return st[-4:]
def main():
  print "Please input your credit card number"
  cc=inputFromUser()
  last4=transform(cc)
  print "CC is [", cc,"]","derived info is [", last4, "]"
  print "Calling erasure"
  erasure(cc)
  print "CC is [", cc,"]","derived info is [", last4, "]"