using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(traverse(new [] {1, 2, 3, 4, 5, 

                                           6, 7, 8, 9, 10, 

                                           11, 12, 13, 14, 15, 

                                           16, 17, 18, 19, 20, 

                                           21, 22, 23, 24, 25}, 

                                   5, 5));

    }

    static int getIndex(int x, int y, int colums)

    {

      return y + x * colums;

    }

​

    static String traverse(int[] matrix, int rows, int columns)

    {

      String output = traverseRecursive(matrix, columns, 0, rows-1, 0, columns-1);

      return output.Substring(0, output.Length - 2);

    }

​

    static String traverseRecursive(int[] matrix, int columns, int rowStart, int rowLength, int colStart, int colLength)

    {

      String output = "";

      for (int i = rowStart; i <= colLength; i++)

      {

        output += matrix[getIndex(rowStart, i, columns)] + ", ";

      }

      for (int i = rowStart+1; i <= rowLength; i++)

      {

        output += matrix[getIndex(i, colLength, columns)] + ", ";

      }

      if (rowStart+1 <= rowLength)

      {

        for(int i = colLength-1; i >= colStart; i--)

        {

          output += matrix[getIndex(rowLength, i, columns)] + ", ";

        }

      }

      if (colStart+1 <= colLength)

      {

        for(int i = rowLength-1; i >= rowStart; i--)

        {

          output += matrix[getIndex(i, colStart, columns)] + ", ";

        }

      }

​

      if(rowStart+1 <= rowLength-1 && colStart+1 <= colLength-1)

      {

        output += traverseRecursive(matrix, columns, rowStart+1, rowLength-1, colStart+1, colLength-1);

      }

​

      return output;

    }

​

}