using System;

using System.IO;

using System.Collections.Generic;

​

public class MaxSum

{

    public static void Main(string[] args)

    {

        string lines = @"215

193 124

117 237 442

218 935 347 235

320 804 522 417 345

229 601 723 835 133 124

248 202 277 433 207 263 257

359 464 504 528 516 716 871 182

461 441 426 656 863 560 380 171 923

381 348 573 533 447 632 387 176 975 449

223 711 445 645 245 543 931 532 937 541 444

330 131 333 928 377 733 017 778 839 168 197 197

131 171 522 137 217 224 291 413 528 520 227 229 928

223 626 034 683 839 053 627 310 713 999 629 817 410 121

924 622 911 233 325 139 721 218 253 223 107 233 230 124 233";

        long ans = 0;

        List<List<int>> numbers = new List<List<int>>();

        foreach (string line in lines.Split('\n')) numbers.Add(getNumbers(line));

​

        //initialise a lookup table filled with 0

        long[][] table = new long[numbers.Count][];

        for (int i = 0; i < numbers.Count; ++i) table[i] = new long[numbers[i].Count];

​

        //first entry is the top number

        table[0][0] = numbers[0][0];

​

        //propagate sum starting from top to last second row

        for (int i = 0; i < numbers.Count - 1; ++i) propagateSum(numbers, table, i);

​

        //answer is the maximum of numbers in last row

        foreach (long num in table[numbers.Count - 1]) ans = Math.Max(ans, num);

​

        //if ans is -1 or 0 -> No answer found.

        Console.WriteLine(ans);

    }

​

    //propagate sum down, left and right

    static void propagateSum(List<List<int>> numbers, long[][] table, int index)

    {

        for (int j = 0; j < numbers[index].Count; ++j)

        {

            //number is prime nothing will pass here.

            if (table[index][j] == -1) continue;

​

            if (isPrime(numbers[index + 1][j])) table[index + 1][j] = -1;

            else

            {

                long downSum = table[index][j] + numbers[index + 1][j];

                table[index + 1][j] = Math.Max(table[index + 1][j], downSum);

            }

​

            if (j != 0 && isPrime(numbers[index + 1][j - 1])) table[index + 1][j - 1] = -1;

            else if (j != 0)

            {

                long leftSum = table[index][j] + numbers[index + 1][j - 1];

                table[index + 1][j - 1] = Math.Max(table[index + 1][j - 1], leftSum);

            }

​

            if (j != numbers[index].Count - 1 && isPrime(numbers[index + 1][j + 1])) table[index + 1][j + 1] = -1;

            else

            {

                long rightSum = table[index][j] + numbers[index + 1][j + 1];

                table[index + 1][j + 1] = Math.Max(table[index + 1][j + 1], rightSum);

            }

​

​

​

        }

    }

​

    //parse a line into an array of numbers

    static List<int> getNumbers(string line)

    {

        List<int> list = new List<int>();

        foreach (string num in line.Split(' ')) list.Add(int.Parse(num));

        return list;

    }

​

    static bool isPrime(int num)

    {

        if (num == 2 || num == 1) return true;

        if (num % 2 == 0) return false;

        for (int i = 3; i < num / 2; i += 2) if (num % i == 0) return false;

        return true;

    }

}