#include <iostream>
using namespace std;
int n, i, j, a[100][100];
int solve(int x, int y) {
int u, v;
if (x == n) return a[x][y];
u = solve(x + 1, y);
v = solve(x + 1, y + 1);
if (u > v) return a[x][y] + u;
else return a[x][y] + v;
}
int main( ) {
cin >> n;
for (i = 1; i <= n; i++)
for (j = 1; j <= i; j++) cin >> a[i][j];
cout << solve(1, 1) << endl;
return 0;
} 输入：
5
2
-1 4
2 -1 -2
-1 6 4 0
3 2 -1 5 8
输出：1
