#!/usr/bin/python

import sys

def fib(n):
    if n >= 0:
        b=n*(fib(n-1))
        #fib(n-1)
        return b
        
if __name__ == '__main__':
    n=raw_input('Please enter how many fibonacci numbers you would like: ')
    n=int(n)
    print fib(n)
