static void Main()
        {
            JuniorTrainer juniorTrainer1 = new JuniorTrainer("Pesho", "Peshov", 24);
            JuniorTrainer juniorTrainer2 = new JuniorTrainer("GonlineStudentho", "GonlineStudentov", 27);
            JuniorTrainer juniorTrainer3 = new JuniorTrainer("Vladko", "Vladov", 19);
            SeniorTrainer seniorTrainer1 = new SeniorTrainer("Petko", "Petkov", 33);
            SeniorTrainer seniorTrainer2 = new SeniorTrainer("Stefan", "Stefanov", 38);
            SeniorTrainer seniorTrainer3 = new SeniorTrainer("Martin", "Martinov", 29);
            GraduateStudent graduateStudent1 = new GraduateStudent("Ivan", "Novakov", 35, "30020925", 4.45f);
            GraduateStudent graduateStudent2 = new GraduateStudent("RadonlineStudentlav", "Simeonov", 28, "30058925", 5.80f);
            GraduateStudent graduateStudent3 = new GraduateStudent("Teodor", "Stoychev", 33, "300521345", 3.00f);
            DropoutStudent dropoutStudent1 = new DropoutStudent("Nakovalnq", "Nakovalnev", 35, "30020925", 4.45f, "...");
            DropoutStudent dropoutStudent2 = new DropoutStudent("Mmmm", "IdropOut", 28, "30058925", 5.80f, "I dropoutStudentn't care zzzZZZzzz...");
            DropoutStudent dropoutStudent3 = new DropoutStudent("Arnold", "Ill' be back", 33, "300521345", 3.00f, "Terminated!!!");
            OnlineStudent onlineStudent1 = new OnlineStudent("Emil", "Stefanov", 48, "40018512", 3.33f, "OOP");
            OnlineStudent onlineStudent2 = new OnlineStudent("Martin", "Todorov", 22, "40065415", 5.45f, "OOP");
            OnlineStudent onlineStudent3 = new OnlineStudent("Valeri", "Zahariev", 18, "40018525", 4.89f, "OOP");
            OnsiteStudent onsiteStudent1 = new OnsiteStudent("Natalya", "Alexandrova", 31, "40089564", 4.00f, "OOP", 5);
            OnsiteStudent onsiteStudent2 = new OnsiteStudent("Adriyana", "Alexandrova", 25, "40012188", 5.25f, "OOP", 5);
            OnsiteStudent onsiteStudent3 = new OnsiteStudent("Peter", "Simeonov", 30, "40035698", 3.80f, "OOP", 3);

            juniorTrainer1.CreateCourse("Drink brave!");
            seniorTrainer1.CreateCourse("I'm alive!");
            seniorTrainer2.DeleteCourse("Drink brave!");
            dropoutStudent3.Reapply();

            List<Person> softUniPersons = new List<Person>()
            { 
                juniorTrainer1,
                juniorTrainer2,
                juniorTrainer3,
                seniorTrainer1,
                seniorTrainer2,
                seniorTrainer3,
                graduateStudent1,
                graduateStudent2,
                graduateStudent3,
                dropoutStudent1,
                dropoutStudent2,
                dropoutStudent3,
                onsiteStudent1,
                onsiteStudent2,
                onsiteStudent3,
                onlineStudent1,
                onlineStudent2,
                onlineStudent3 
            };

            SULS testSoftUni = new SULS(softUniPersons);
            testSoftUni.ExtractCurrentStudents();
            
        }