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

import sys

def factorial(n):
    if n == 0:
        return 1
    else:
        return n*factorial(n-1)
        
print "Escribe un numero: "
num = int( sys.stdin.readline() )
print "El factorial de %d es %s" % ( num, factorial(num) )