Longest sequnce

using System;
//We are given a matrix of strings of size N x M. Sequences in the matrix we define as sets of several neighbor
//elements located on the same line, column or diagonal. Write a program that finds the longest sequence of equal strings in the matrix
class Program
{

    static int bestMatch = 1;
    static string bestString = "";

    static void Main()
    {
        string[,] matrix = {
                        {"ha","yo","hi","hi","hi","jo"},
                        {"ha","bo","yo","go","go","go"},
                        {"ha","bo","li","yo","li","li"},
                        {"bo","li","li","li","yo","li"},
                        };

        for (int x = 0; x < matrix.GetLength(0); x++)
        {
            for (int y = 0; y < matrix.GetLength(1); y++)
            {
                Seek(x, y, matrix);
            }
        }
        //print result
        for (int i = 0; i < bestMatch; i++)
        {
            if (i == 0)
            {
                Console.Write(bestString);
            }
            else
            {
                Console.Write("," + bestString);
            }
        }
        Console.WriteLine();
    }

    private static void Seek(int x, int y, string[,] matrix)
    {
        int match = 0;
        string test = matrix[x, y];
        //check horizontal
        for (int row = x, col = y; col < matrix.GetLength(1); col++)
        {
            if (test == matrix[row, col])
            {
                match++;
            }
        }
        CheckForBestScore(match, test);
        match = 0;
        //check diagonal down
        for (int row = x, col = y; row < matrix.GetLength(0) && col < matrix.GetLength(1); row++, col++)
        {
            if (test == matrix[row, col])
            {
                match++;
            }
        }
        CheckForBestScore(match, test);
        match = 0;
        //check diagonal up
        for (int row = x, col = y; row >= 0 && col >= 0; row--, col--)
        {
            if (test == matrix[row, col])
            {
                match++;
            }
        }
        CheckForBestScore(match, test);
        match = 0;
        //check vertical
        for (int row = x, col = y; row < matrix.GetLength(0); row++)
        {
            if (test == matrix[row, col])
            {
                match++;
            }
        }
        CheckForBestScore(match, test);
    }

    private static void CheckForBestScore(int match, string test)
    {
        if (match > bestMatch)
        {
            bestMatch = match;
            bestString = test;
        }

    }
}