Day9.py

'''

Objective 
Today, we're learning and practicing an algorithmic concept called Recursion. Check out the Tutorial tab for learning materials and an instructional video!

Recursive Method for Calculating Factorial 
Task 
Write a factorial function that takes a positive integer,  as a parameter and prints the result of  ( factorial).

Note: If you fail to use recursion or fail to name your recursive function factorial or Factorial, you will get a score of .

Input Format

A single integer,  (the argument to pass to factorial).

Constraints

Your submission must contain a recursive function named factorial.
Output Format

Print a single integer denoting .

Sample Input

3
Sample Output

6
Explanation

Consider the following steps:

From steps  and , we can say ; then when we apply the value from  to step , we get . Thus, we print  as our answer.

'''

#!/bin/python3

import math
import os
import random
import re
import sys

# Complete the factorial function below.
def factorial(n):
    if(n==0):
        return 1
    elif(n == 1):
        return 1
    else:
        return n*factorial(n-1)


if __name__ == '__main__':
    fptr = open(os.environ['OUTPUT_PATH'], 'w')

    n = int(input())

    result = factorial(n)

    fptr.write(str(result) + '\n')

    fptr.close()