students

class Student
    {
        public string Name;
        public List<int> Marks;
        public int ResultMark;

        private double average_mark;
        private int[,] BetterMarks;
        private int sum;

        // Конструкторы
        public Student(string input)
        {
            var temp = input.Split();
            Name = temp[0];
            Marks = new List<int>();
            for (int i = 1; i < temp.Length; i++)
            {
                Marks.Add(Int32.Parse(temp[i]));
            }
            Analyse();
        }
        public Student(string name, List<int> a)
        {
            Name = name;
            Marks = a;
            Analyse();
        }

        // Методы
        private void Analyse()
        {
            sum = 0;
            foreach(var i in Marks)
            {
                sum += i;
            }
            GetAverageMark();
            ResultMark = GetRusultMark(average_mark);
            GetBetterMarks();
        }

        private void GetAverageMark()
        {
            average_mark = 0;
            foreach (var i in Marks)
            {
                average_mark += i;
            }
            average_mark = GetAverage(average_mark, Marks.Count);
        }
        private int GetRusultMark(double c)
        {
            return (int)(c + 0.5);
        }
        private double GetAverage(double sum, int count) {
            return sum / count;
        }
        private void GetBetterMarks()
        {
            BetterMarks = new int[6, 6];
            for (int i = 0; i < 6; i++)
            {
                // q - оценка, которой будем улучшать
                for (int q = i; q < 6; q++)
                {
                    if (i > ResultMark)
                    {
                        int j = 0;
                        for (j = 0; GetRusultMark(GetAverage(sum + j * q, Marks.Count + j)) != i; j++) ;
                        BetterMarks[i, q] = j;
                    }
                }
            }
        }

        public override string ToString()
        {
            string result = "Info about student " + Name + "\n" + "Marks: ";
            for (int i = 0; i < Marks.Count; i++)
            {
                result += Marks[i].ToString();
                if (i != Marks.Count - 1)
                {
                    result += ", ";
                }
            }
            result += '\n' + "Result mark – " + ResultMark.ToString() + '\n';

            for (int i = 0; i < 6; i++)
            {
                for (int j = 0; j < 6; j++)
                {
                    if (BetterMarks[i, j] != 0)
                    {
                        result += "To get " + i.ToString() + " you have to get " + BetterMarks[i, j].ToString() + " marks " + j.ToString() + '\n';
                    }
                }
            }

            return result;
        }
    }