Problem:
Factorial

Write a program which reads an integer n and prints the factorial of n. You can assume that n ≤ 20.

Input

An integer n (1 ≤ n ≤ 20) in a line.

Output

Print the factorial of n in a line.

Sample Input

5

Output for the Sample Input

120

Solution in JAVA (judge verdict: Wrong Answer)

import java.util.Scanner;

public class Main{
	public static int factorial(int n){
		if( n == 0 ){
			return 1;
		}
		return n*factorial(n-1);
	}
	
	public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		
		int n = stdIn.nextInt();
		System.out.println(factorial(n));
	}
}