using System;

using System.Text.RegularExpressions;

using System.Linq;

public class Program

{

      public static void Main(string[] args)

        {

​

            string numbers = @" 

                                 1

                               8 4

                              2 6 9

                             8 5 9 3";

​

            string[] linesArr = numbers.Split('\n');

            int[,] numbers2DArr = ConvertStringTo2DArray(linesArr);

            for (int i = 0; i < linesArr.Length; i++)

            {

                int[] singleC = Regex.Matches(linesArr[i], "[0-9]+").Cast<Match>().Select(m => int.Parse(m.Value)).ToArray();

                for (var column = 0; column < singleC.Length; column++)

                    numbers2DArr[i, column] = singleC[column];

            }

            for (var i = 0; i < numbers2DArr.GetLength(0); i++)

            {

                for (var j = 0; j < numbers2DArr.GetLength(0); j++)

                {

                    if (numbers2DArr[i, j] == 0) continue;

                    if (IsPrime(numbers2DArr[i, j]))

                    {

                        numbers2DArr[i, j] = 0;

                    }

                }

            }

            int[,] tempResult = numbers2DArr;

            for (int i = numbers2DArr.GetLength(0) - 2; i >= 0; i--)

            {

                for (var j = 0; j < numbers2DArr.GetLength(0); j++)

                {

                    int c = tempResult[i, j];

                    int a = tempResult[i + 1, j];

                    int b = tempResult[i + 1, j + 1];

                    if ((!IsPrime(c) && !IsPrime(a)) || (!IsPrime(c) && !IsPrime(b)))

                        numbers2DArr[i, j] = c + Math.Max(a, b);

                }

            }

​

            Console.WriteLine(numbers2DArr[0, 0]);

        }

​

        public static bool IsPrime(int number)

        {

            if ((number & 1) == 0)

            {

                if (number == 2)

                {

                    return true;

                }

                return false;

            }

​

            for (var i = 3; i * i <= number; i += 2)

            {

                if (number % i == 0)

                {

                    return false;

                }

            }

            return number != 1;

        }

​

        public static int[,] ConvertStringTo2DArray(string[] numbers)

        {

            int[,] numbers2DArr = new int[numbers.Length, numbers.Length + 1];

​

            for (int row = 0; row < numbers.Length; row++)

            {

                string[] singleR = numbers[row].Trim().Split(' ');

​

                for (int column = 0; column < singleR.Length; column++)

                {

                    int number;

                    int.TryParse(singleR[column], out number);

                    numbers2DArr[row, column] = number;

                }

            }

            return numbers2DArr;

        }

}