#include <iostream>
#include <cstdio>

using namespace std;
int input(){
    int res = 0; char c = ' ';
    while (c < '0') c = getchar();
    while (c >= '0') res = res * 10 + (c - '0'), c = getchar();
    return res;
}
const int N = 1e3 + 1;

int a[N][N], n;
int main(){
    while (cin >> n){
        int ans = 0;
        for (int i = 1; i <= n; ++ i)
            for (int j = 1; j <= i; ++ j)
                a[i][j] = max(a[i - 1][j], a[i - 1][j - 1]) + input();
        for (int j = 1; j <= n; ++ j)
            ans = max(ans, a[n][j]);
        for (int i = 1; i <= n; ++ i)
            for (int j = 1; j <= i; ++ j)
                a[i][j] = 0;
        cout << ans << "\n";
    }
}