import java.util.Scanner;

public class Factorial
{
    public Factorial()
    {
        System.out.println("Please type in a number to get n!, type \"exit\" when you are done:");
        Scanner sc = new Scanner(System.in);  
       
        while(sc.hasNext()){ 
            String str = sc.next(); 
            if(str.equals("exit"))
                break;
            System.out.println(str + "! = " + factorial(Integer.parseInt(str)));
        }
    }

    public int factorial(int n){
        if(n==0 || n==1)
            return 1;
        else
            return n * factorial(n-1);
    }
    
    public static void main(String args[]){
        Factorial s = new Factorial();
    }
}