using System;

​

namespace MyApplication

{

  class Program

  {

    static void checkAge(int age)

    {

      if (age < 18)

      {

        throw new ArithmeticException("Access denied - You must be at least 18 years old.");

      }

      else

      {

        Console.WriteLine("Access granted - You are old enough!");

      }

    }

​

    static void Main(string[] args)

    {

      checkAge(20);

    }

  }

}