#include "stdafx.h"
#include <iostream>
using namespace std;
int _tmain(int argc, _TCHAR* argv[])
{
int depth = 0;
cin >> depth;
int **temp = new int*[depth];
for (int i = 0; i < depth; i ++)
{
temp[i] = new int[depth]();
for (int j = 0; j <= i; j ++)
{
cin >> temp[i][j];
}
}
for (int i = depth - 2; i >= 0; i --)
{
for (int j = 0; j <= i; j ++)
{
temp[i][j] += max(temp[i + 1][j], temp[i + 1][j + 1]);
}
}
cout << temp[0][0];
for (int i = 0; i < depth; i ++)
delete [] temp[i];
delete [] temp;
return 0;
}