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.*;

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