A. Factorial
time limit per test
2 seconds
memory limit per test
64 megabytes
input
stdin
output
stdout

Print the factorial of the given integer number n. The factorial of n is equal to 1·2·...·n.

Input

The only line contains n (1 ≤ n ≤ 10).

Output

Print the factorial of n.

Examples
Input
3
Output
6
Input
5
Output
120