HackerRank - connected Cell in a grid - return count

ConnectedCellInaGridReturnCount.cs

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

namespace ConnectCellInaGrid_Count
{
    class Program
    {
        static void Main(string[] args)
        {   // 2:40pm - 3:08pm 
            int row = Convert.ToInt32(Console.ReadLine());
            int col = Convert.ToInt32(Console.ReadLine());

            int[,] arr = new int[row, col];

            for (int i = 0; i < row; i++)
            {
                string s = Console.ReadLine();

                int j = 0;
                foreach (char c in s)
                {
                    if (c == '0' || c == '1')
                    {
                        arr[i, j] = c -'0';
                        j++;
                    }
                }

            }

            int max = 0;
            for (int i = 0; i < row; i++)
                for (int j = 0; j < col; j++)
                {
                    int cur = getRegionCount(arr, i, j);
                    if (cur > max)
                        max = cur;
                }

            Console.WriteLine(max);
        }

        public static int getRegionCount(int[,] arr, int i, int j)
        {
            int row = arr.GetLength(0);
            int col = arr.GetLength(1);

            if (isInRange(i, j, row, col) && arr[i, j] == 1)
            {
                arr[i, j] = 2;

                return 1 +
                    getRegionCount(arr, i - 1, j - 1) +
                    getRegionCount(arr, i - 1, j) +
                    getRegionCount(arr, i - 1, j + 1) +
                    getRegionCount(arr, i, j - 1) +
                    getRegionCount(arr, i, j + 1) +
                    getRegionCount(arr, i + 1, j - 1) +
                    getRegionCount(arr, i + 1, j) +
                    getRegionCount(arr, i + 1, j + 1);
            }
            else
                return 0; 
        }

        private static bool isInRange(int i, int j, int row, int col)
        {
            if (i >= 0 && i < row && j >= 0 && j < col)
                return true;
            else
                return false; 
        }
    }
}