519 - Factorial n (n!)

Factorial n (n!)

Time Limit: 1 sec

**The Problem**

Factorial n is written as n! and n! = 1∗2∗3∗. . .∗(n−1)∗n.

For example,

0! = 1

1! = 1

2! = 1 x 2 = 2

3! = 1 x 2 x 3 = 6

4! = 1 x 2 x 3 x 4 = 24

5! = 1 x 2 x 3 x 4 x 5 = 120

etc.

Given an integer number n, you will have to find out the value of n!.

**The Input**

Input file contain a series of line, each line contain one integer numbers **n** (0<=**n**<20. Input is terminated by **EOF**.

**The Output**

For each line of input, output will show the value of **n!** in a separate line.

**Sample Input**

3

5

9

**Sample Output**

6

120

362880

Problem Setter: Shahin ShamS