#! /usr/bin/python
# -*- coding: iso-8859-1 -*-

"""
Problem from:  http://www.umassd.edu/mathcontest/9999.cfm

Determine the ones digits for the following expression:
0! + 1! + 2! + 3! + 4! + . . . + 9998! + 9999!

Result:
python factorialOnes.py 9999
Numbers of digits '1' in this factorial expression:  4000

Author: Cesar Kallas	-	cesarkallas at gmx . net
http://cesarkallas.soulivre.org
Date: 28/10/2006
"""

import sys

def factorial(num):
	f = 1
	ones = 0
	while (num > 0):
		f = f * num
		ones = ones + str(num).count("1")
		#print num, "   "
		num = num - 1
	return ones, f

if __name__ == "__main__":
	if len(sys.argv) < 2:
		print "Usage: python %s factorial" % sys.argv[0]
		sys.exit()
	else:
		ones, fat = factorial(int(sys.argv[1]))
		print "Fatorial of %s is: " % sys.argv[1], fat
		print "Numbers of digits '1' in this factorial expression: ", ones