using System;
public class Program
{
public static void Main()
//Get User Input
Console.Write("Enter a number: ");
int num = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("The factorial of {0}! is {1}",num,factorial(num));
}
private static int factorial(int num){
int result;
//Stop => Return to Upper Level
if(num == 1){
return 1;
}else{
//Call next level
result = factorial(num-1) * num;
//Return result
return result;