public StudentsList(int[] StudentsMark1, int[] StudentsMark2, int[] StudentsMark3)
        {
            Student Student1 = new Student(StudentsMark1);
            Student Student2 = new Student(StudentsMark2);
            Student Student3 = new Student(StudentsMark3);

            _studentsAverageMark = new double[count];

            _studentsAverageMark[0] = Student1.CalcAverageMark();
            _studentsAverageMark[1] = Student2.CalcAverageMark();
            _studentsAverageMark[2] = Student3.CalcAverageMark();
        }