1 import java.util.Scanner;
2
3 public class Main {
4
5 public static void main(String[] args) {
6 // TODO Auto-generated method stub
7 Scanner input = new Scanner(System.in);
8 int n = input.nextInt();
9 int [][]a=new int [n][n];
10 for(int i = 0;i<n;i++) {
11 for(int j = 0;j <= i;j++ ) {
12 a[i][j] =input.nextInt();
13 }
14 }
15 System.out.println(add(a,n));
16 input.close();
17
18 }
19 public static int add(int [][]b,int n) {
20 for(int i = n-2;i>=0;i--) {
21 for(int j = 0;j <= i;j++ ) {
22 b[i][j]+=max(b[i+1][j],b[i+1][j+1]);
23 }
24 }//这里从下向上进行判定。不然从上向下的还要进行再次比较大小。
25 return b[0][0];
26
27 }
28 public static int max (int a,int b) {
29 if(a>b)return a;
30 else return b;
31 }
32
33 }
