using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

    public class ClassRoom

    {

        readonly Student[,] students = new Student[10, 10];

        int RowToIndex(string row)

        {

            string temp = row.ToUpper();

            return (temp[0] - 'A');

        }

        public Student this[string row, int column]

        {

            get 

            {

                return students[RowToIndex(row), column - 1];

            }

            set 

            {

                students[RowToIndex(row), column - 1] = value;

            }

        }

    }

    public class Student

    {

    }

}