public static void MenouHeadMaster(int hm_id)
        {
            using (MyContext db = new MyContext())
            {
                Console.WriteLine($"\nHello {db.HeadMasters.Find(hm_id).FirstName},\n");
                while (1 == 1)
                {
                    try
                    {
                        Console.WriteLine("");
                        Console.WriteLine("1 - Add a Student");
                        Console.WriteLine("2 - Update a Student");
                        Console.WriteLine("3 - Delete a Student");
                        Console.WriteLine("4 - Add a Trainer");
                        Console.WriteLine("5 - Update a Trainer");
                        Console.WriteLine("6 - Delete a Trainer");
                        Console.WriteLine("7 - Add a Course");
                        Console.WriteLine("8 - Update a Course");
                        Console.WriteLine("9 - Delete a Course");
                        Console.WriteLine("10 - Add an Assignment");
                        Console.WriteLine("11 - Update an Assignment");
                        Console.WriteLine("12 - Delete an Assignment");
                        Console.WriteLine("13 - Add a Head-Master");
                        Console.WriteLine("14 - Delete a Head-Master");
                        Console.WriteLine("15 - Relate Courses and Students(students per courses)");
                        Console.WriteLine("16 - UN-Relate Courses and Students(students per courses)");
                        Console.WriteLine("17 - Relate Trainers and Courses(Trainers per courses)");
                        Console.WriteLine("18 - UN-Relate Trainers and Courses(Trainers per courses)");
                        Console.WriteLine("19 - Relate Assignments and Courses(Assignments per courses)");
                        Console.WriteLine("20 - UN-Relate Assignments and Courses(Assignments per courses)");
                        Console.WriteLine("21 - Relate Assignments and Students(Assignments per Students)");
                        Console.WriteLine("22 - UN-Relate Assignments and Students(Assignments per Students)");



                        Console.WriteLine("23 - Exit from the programme");
                        Console.WriteLine("Please select one of the options: ");
                        int user_chioce = Convert.ToInt32(Console.ReadLine());

                        switch (user_chioce)
                        {
                        case 1:
                            StudentsManager.AddStudent();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 2:
                            StudentsManager.UpdateStudent();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 3:
                            StudentsManager.DeleteStudent();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 4:
                            TrainerManager.AddTrainer();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 5:
                            TrainerManager.UpdateTrainer();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 6:
                            TrainerManager.DeleteTrainer();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 7:
                            CourseManager.AddCourse();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 8:
                            CourseManager.UpdateCourse();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 9:
                            CourseManager.DeleteCourse();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 10:
                            AssignmentManager.AddAssignment();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 11:
                            AssignmentManager.UpdateAssignment();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 12:
                            AssignmentManager.DeleteAssignment();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 13:
                            HeadMasterManager.AddHeadMaster();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 14:
                            HeadMasterManager.DeleteHeadMaster();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 15:
                            StudentsManager.RelateStudentsCourses();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 16:
                            StudentsManager.UNRelateStudentsCourses();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 17:
                            TrainerManager.RelateCoursesToTrainers();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 18:
                            TrainerManager.UNRelateCoursesToTrainers();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 19:
                            CourseManager.RelateAssignmentsToCourses();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 20:
                            CourseManager.UNRelateAssignmentsToCourses();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 21:
                            StudentsManager.RelateStudentsAssignments();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;

                        case 22:
                            StudentsManager.UNRelateStudentsAssignments();
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            break;


                        case 23:
                            Environment.Exit(0);
                            break;
                        }
                    }
                    catch (Exception)
                    {
                        Console.WriteLine("Wrong input");
                    }
                }
            }
        }