static void ShowMainMenu()
        {
            Console.WriteLine("Welcome to Dufflin/Munder Cardboard Co. Sales Portal!\n" +
                              "\n1. Enter Sales\n" +
                              "2. Generate Report for Accountant\n" +
                              "3. Add New Sales Employee\n" +
                              "4. Find a Sale\n" +
                              "5. Exit");

            int menuSelection = 0;

            try
            {
                menuSelection = Convert.ToInt32(Console.ReadLine());
            }
            catch (FormatException)
            {
                Console.WriteLine($"Please enter a number 1-5 to select an action. Please return to the main menu and try again.\n");
                Program.BackToStart();
            }

            switch (menuSelection)
            {
            case 1:
                Sale.EnterASale();
                break;

            case 2:
            {
                Console.Clear();
                var accountants = Company.AccountantEmployees;
                var salespeople = Company.SalesEmployees;
                Console.WriteLine("Which accountant would you like to generate the report for?");
                accountants.ForEach(accountant => Console.WriteLine(accountant.Name));

                var answer   = Console.ReadLine();
                var textInfo = new CultureInfo("en-US", false).TextInfo;
                if (answer.ToLower() == "angela" || answer.ToLower() == "oscar")
                {
                    Console.Clear();
                    var s = 1;
                    Console.WriteLine("Monthly Sales Report\n" +
                                      $"For: {textInfo.ToTitleCase(answer)}\n");
                    salespeople.ForEach(salesperson =>
                        {
                            Console.WriteLine($"{s}. {salesperson.Name}\n" +
                                              $"   Clients:");
                            salesperson.PrintClients();
                            s++;

                            Console.WriteLine($"Total: ${salesperson.SumSales()}\n");
                        });
                }
                else
                {
                    Console.WriteLine("Please enter a valid accountant selection:\n" +
                                      "Angela\n" +
                                      "Oscar\n");
                }
                Program.BackToStart();
                break;
            }

            case 3:
                Company.addNewEmployee();
                break;

            case 4:
            {
                Sale.FindASale();
                break;
            }

            case 5:
                Environment.Exit(0);
                break;

            default:
                Console.WriteLine("Please enter a number 1-5");
                break;
            }
        }