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{
    public static void main(String args[]){
     Scanner sc =new Scanner(System.in);
     int n = sc.nextInt();
    System.out.println(f(n));
   }
    public static int f(int n){
       return n==1?1:n+f(n-1);
    }
}