using System;

using System.IO;

public class Program

{

    // FUN: Read the file and convert it to bidimentionl array int

    private static int[][] fileToPyramid(string path) {

        string[] fileStr = null;

        try

        {

            fileStr = File.ReadAllLines(path);

        }

        catch (IOException e) {

            Console.WriteLine(e.Message);

            return null;

        }

        if (fileStr == null)

            return null;

        int[][] pyramid = new int[fileStr.Length][];

        int i = 0;

        try {

            foreach (string line in fileStr) {

                pyramid[i] = Array.ConvertAll(line.Split(' '), int.Parse);

                i++;

            }

        }

        catch (Exception e) {

            Console.WriteLine(e.Message);

            return null;

        }

        return pyramid;

    }

    // FUN: Check if a number is prime or not

    private static bool isPrime(int n) {

        int m = n / 2;

        if (n == 1)

            return false;

        for(int i = 2; i <= m; i++)    

        {    

            if(n % i == 0)    

                return false;

        }

        return true;

    }

    // FUN: Recursive solver, reading the pyramid and return the final result in var res.

    private static int solve_it(int[][] pyramid, int x, int y, int ret, int res, int length, int stopRet) {

        if (y >= length) {      

            if (ret > res){

                res = ret;

            }

            return res;

        }

        if (isPrime(pyramid[y][x]) == true && stopRet == 0) {

            res = solve_it(pyramid, x+1, y, ret, res, length, 1);

            }

        if (isPrime(pyramid[y][x]) == true && stopRet == 1){        

            if (ret > res){

                res = ret;

            }

            return res;

        }

        ret += pyramid[y][x];

        res = solve_it(pyramid, x, y+1, ret, res, length, 0);

        if (stopRet == 0) {

            ret -= pyramid[y][x]; 

            res = solve_it(pyramid, x+1, y, ret, res, length, 1);

        }

        return res;

    }

    private static int[][] sample() {

        int[][] pyramid = 

        {

            new int[] { 1 },

            new int[] { 8, 4 },

            new int[] { 2, 6, 9 },

            new int[] { 8, 5, 9, 3 }

        };

        return pyramid;

    }

    // FUN: Launch the solver

    // INPUT: enter the path to your file - Enter "test" to test with the sample

    // WARNING: Using a local file will give you the 'System.Security.Permissions.FileIOPermission', compile it on local to be able to access to your local file.

    private static void solve() {

        int[][] pyramid;

        string path;

        string chooseFile = Console.ReadLine();

        if (chooseFile == "test")

            pyramid = sample();

        else {

            path = Console.ReadLine();

            pyramid = fileToPyramid(path);

        }

        if (pyramid == null)

            return ;

        int res = pyramid[0][0];

        if (pyramid[1] == null) {

            return ;

        }

        Console.WriteLine("RESULT = " + solve_it(pyramid, 0, 1, pyramid[0][0], pyramid[0][0], pyramid.Length, 0));

    }

​

    // FUN: Main

    public static void Main()

    {

        solve();

    }

}