//

 // Created by snnnow on 2020/7/23

 //

 //递归算法，除了慢其实还好

 #include<iostream>

 #include<stdio.h>

 #include<stdlib.h>

 #include<time.h>

 #include <queue>

 using namespace std;

 #define Max 101

 int m[Max][Max];

 int n;

 int dfs(int a,int b){

     if(a==n)

         return m[a][b];

     return max(dfs(a+,b),dfs(a+,b+))+m[a][b];

 }

 int main(){

     scanf("%d",&n);

     for (int i = ; i <= n; ++i) {

         for (int j = ; j <= i ; ++j) {

             scanf("%d",&m[i][j]);

         }

     }

     printf("%d",dfs(,));

 }

 //

 // Created by snnnow on 2020/7/23

 //

 //递归算法，除了慢其实还好

 #include<iostream>

 #include<stdio.h>

 #include<stdlib.h>

 #include<time.h>

 #include <queue>

 #include <time.h>

 using namespace std;

 #define Max 101

 int m[Max][Max];

 int rem[Max][Max];

 int n;

 int dfs(int a,int b){

     if(rem[a][b]!=-)

         return rem[a][b];

     if(a==n)

         rem[a][b]= m[a][b];

     else

         rem[a][b]=max(dfs(a+,b),dfs(a+,b+))+m[a][b];

     return rem[a][b];

 }

 int main(){

     scanf("%d",&n);

     for (int i = ; i <= n; ++i) {

         for (int j = ; j <= i ; ++j) {

             scanf("%d",&m[i][j]);

             rem[i][j]=-;

         }

     }

     printf("%d",dfs(,));

     cout<<endl;

     printf("Time used = %.2f\n", (double)clock() / CLOCKS_PER_SEC);

 }