import java.io.File;
import java.io.FileNotFoundException;
import java.util.HashMap;
import java.util.Scanner;



public class main {

    static final String inputFileName = "input.txt"; //input file name which in current directory
    static HashMap<Integer,Boolean> primeList = new HashMap<>(); //create hashmap for keep prime number


    public static void main(String[] args) {
        int line = getTriangleLength(); //determine triangle height

        int arraySize = (line * (line + 1)) / 2; // calculate enough space for keep triangle

        int[] triangle = new int[arraySize]; //create array for keep inputs
        int[] dynamicTriangle; // create dynamic array for use dynamic iterations.
        int[] indexTable = new int[line]; // indexTable keeps start index for each line.

        fillTriangle(triangle); // read input from file and fill arrays
        dynamicTriangle = triangle.clone();
        fillIndexTable(indexTable,line);




        int maxSum = findMaxSum(triangle,dynamicTriangle,indexTable,line); //calculate maxSum

        System.out.println(maxSum);
    }

    static int findMaxSum(int[] triangle,int[] dynamicTriangle,int[] indexTable,int size){
        boolean leftChildIsPrime;
        boolean rightChildIsPrime;
        int leftChild;
        int rightChild;
        int index;

        for (int i = size-1; i > 0 ; i--) {

            for (int j = 0; j <i ; j++) {
                index =indexTable[i];
                leftChild = triangle[index+j];
                rightChild = triangle[index+j+1];
                leftChildIsPrime = isPrime(leftChild);
                rightChildIsPrime = isPrime(rightChild);

                if(!(leftChildIsPrime || rightChildIsPrime)){ //both non prime
                    dynamicTriangle[index+j-i] = dynamicTriangle[index+j-i] + Math.max(dynamicTriangle[index+j],dynamicTriangle[index+j+1]); //update parent on dynamic triangle

                }else if(leftChildIsPrime && !rightChildIsPrime){ //only left is prime
                    dynamicTriangle[index+j-i] = dynamicTriangle[index+j-i] + dynamicTriangle[index+j+1];

                }else if(!leftChildIsPrime){ //only right is prime
                    dynamicTriangle[index+j-i] = dynamicTriangle[index+j-i] + dynamicTriangle[index+j];
                }
            }
        }


        return  dynamicTriangle[0];
    }

    static boolean isPrime(int key){
        if (primeList.containsKey(key)){
            return primeList.get(key);
        }


        for(int i=2;i<=Math.sqrt(key);i++){
            if(key%i==0){
                return false;
            }
        }
        primeList.put(key,true);
        return true;

    }


    static int getTriangleLength(){
        int lineCounter  = 0;
        File file =
                new File(inputFileName);
        try {

            Scanner sc = new Scanner(file);

            while (sc.hasNextLine()){
                lineCounter++;

                sc.nextLine();

            }

        }catch (FileNotFoundException e){
            e.printStackTrace();
        }
        return lineCounter;

    }

    static void fillTriangle(int[] triangle){
        int index=0;
        File file =
                new File(inputFileName);
        try {

            Scanner sc = new Scanner(file);

            while (sc.hasNextInt()){
                triangle[index] = sc.nextInt();
                index++;
            }

        }catch (FileNotFoundException e){
            e.printStackTrace();
        }

    }

    static void fillIndexTable(int[] indexTable,int size){
        for (int i = 0; i <size ; i++) {
            indexTable[i] = (i*(i+1))/2;
        }

    }


}