C# program to calculate Factorial with recursive function

  class Program  
   {  
       static int Factorial(int number)  
       {  
         if (number < 1)  
         {  
           return 0;  
         }  
         else if (number == 1)  
         {  
           return 1;  
         }  
         else  
         {  
           return number * Factorial(number - 1);  
         }  
       }  
       static void Main(string[] args)  
       {  
       Console.Write("Enter a number: ");  
         if (int.TryParse(Console.ReadLine(), out int number))  
         {  
         Console.WriteLine(  
           $"{number:N0}! = {Factorial(number):N0}");  
         }  
         else  
         {  
           Console.WriteLine("You did not enter a valid number!");  
         }  
       Console.ReadLine();  
       }  
     }