 public int Score { get; set; }
        public int AttendancePercentage { get; set; }
        public string GetGrade()
        {
            if(Score > 90 && AttendancePercentage > 70)
                return "A";
            else
                if(Score>80 && AttendancePercentage > 60)
                    return "B";
                else
                    if(Score > 60 & AttendancePercentage > 60)
                        return "C";
                    else
                        return "F";
        }