Largest Frame in Matrix

Largest Frame in Matrix.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Largest_Frame_in_Matrix
{
    public class Program
    {
        public static void Main(string[] args)
        {
            int[] matrixDimensions = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
            int rows = matrixDimensions[0];
            int cols = matrixDimensions[1];
            int[,] matrix = new int[rows, cols];
            FillInMatrix(matrix, rows, cols);
			
            // generate frames (top, left), (bottom, right): 0 <= left <= right <= cols && 0 <= top <= bottom <= rows
            List<string> equalSizedFrames = new List<string>(); // equal sized frames of max size
            int maxSizeFrame = rows * cols; // max size == size matrix
            bool foundFrame = false;
            while (!foundFrame)
            {
                for (int top = 0; top < rows; top++)
                    for (int left = 0; left < cols; left++)
                        for (int bottom = rows - 1; bottom >= top; bottom--)
                            for (int right = cols - 1; right >= left; right--)
                            {
                                bool isMaxSize = IsRequiredSize(top, left, bottom, right, maxSizeFrame);
                                bool hasEqualCells = isEqualCellsFrame(top, left, bottom, right, matrix);
                                if (hasEqualCells && isMaxSize)
                                {
                                    foundFrame = true;
                                    AddCurrentFrameToList(top, left, bottom, right, equalSizedFrames);
                                }
                            }
                if (!foundFrame) maxSizeFrame--;
                else break;
            }
            PrintInAscendingOrder(equalSizedFrames);
        }        
        static void FillInMatrix(int[,] matrix, int rows, int cols)
        {
            for (int row = 0; row < rows; row++)
            {
                int[] cells = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
                for (int col = 0; col < cols; col++)
                    matrix[row, col] = cells[col];
            }
        }
        static bool IsRequiredSize(int top, int left, int bottom, int right, int size)
        {
            int verticalLength = bottom - top + 1;
            int horizontalLength = right - left + 1;
            int areaFrame = horizontalLength * verticalLength;
            return areaFrame == size;
        }
        static void AddCurrentFrameToList(int top, int left, int bottom, int right, List<string> equalSizedFrames)
        {
            int verticalLength = bottom - top + 1;
            int horizontalLength = right - left + 1;
            equalSizedFrames.Add(string.Join("x", verticalLength, horizontalLength));
        }
        static bool isEqualCellsFrame(int top, int left, int bottom, int right, int[,] matrix)
        {
            int cell = matrix[top, left];
            for (int col = left; col <= right; col++)
                if (matrix[top,col] != cell || matrix[bottom,col] != cell)
                    return false;
            for (int row = top; row <= bottom; row++)
                if (matrix[row, left] != cell || matrix[row, right] != cell)
                    return false;
            return true;
        }
        static void PrintInAscendingOrder (List<string> list)
        {
            list.Sort();
            Console.Write(string.Join(", ", list));
        }
    }
}