import java.nio.file.*;
import java.util.Arrays;

import java.io.BufferedReader;
import java.io.InputStreamReader;


public class MaxPathSum {

    public static void main(String[] args) throws Exception {
        // int[][] data = Files.lines(Paths.get("triangle.txt"))
        //         .map(s -> stream(s.trim().split("\\s+"))
        //                 .mapToInt(Integer::parseInt)
        //                 .toArray())
        //         .toArray(int[][]::new);
        // System.out.println(data);

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        // int bla = Integer.parseInt(br.readLine());
        int numberOfLines = 3;
        int[][] pyramidOfNumbers = null;;
        int[] rowInPyramid = null;
        for(int i=0;i<numberOfLines;i++){
            rowInPyramid = Arrays.stream(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
            for(int j=0;j<rowInPyramid.length;j++){
                // System.out.println(i);
                System.out.println(rowInPyramid[j]);

                pyramidOfNumbers[i][j] = rowInPyramid[j];
            }
        }


        for (int r = pyramidOfNumbers.length - 1; r > 0; r--)
            for (int c = 0; c < pyramidOfNumbers[r].length - 1; c++)
                pyramidOfNumbers[r - 1][c] += Math.max(pyramidOfNumbers[r][c], pyramidOfNumbers[r][c + 1]);

        System.out.println(pyramidOfNumbers[0][0]);
    }
}