#include <iostream>
#include <cstdio>
#include <cassert>
#include <ctime>
#include <cmath>
#include <cstring>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <unordered_map>
#include <set>

using namespace std;

#ifdef LOCAL
#define dbg(x) cerr << #x " = " << x << endl;
#include "pretty_print.h"
#else
#define dbg(x)
#endif

typedef long double ld;
typedef long long ll;
typedef unsigned long long ull;

#define snd second
#define fst first

template <typename T> T sqr(T x) { return x * x; }
template <typename T> T abs(T x) { return x < 0? -x : x; }
template <typename T> T gcd(T a, T b) { return b? gcd(b, a % b) : a; }
template <typename T> bool chmin(T &x, const T& y) { if (x > y) { x = y; return true; } return false; }
template <typename T> bool chmax(T &x, const T& y) { if (x < y) { x = y; return true; } return false; }

#define X first
#define ID second
#define P second


const int LIMIT_ITER = 2e+8;


int main(int /* argc */, char** /* argv */)
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    #ifdef LOCAL
    assert(freopen("inp", "r", stdin));
    assert(freopen("out", "w", stdout));
    #endif

    int n;
    while (cin >> n) {
        int max_iter = LIMIT_ITER / n;
        dbg(max_iter);
        ll s[n + 1];
        ll q[n + 1];
        s[0] = 0;
        q[0] = 0;
        for (int i = 1; i <= n; ++i) {
            ll x;
            cin >> x;
            s[i] = s[i - 1] + x;
            q[i] = q[i - 1] + x * x;
        }

        ll answer = 0;
        set < pair <ll, int> > b;
        for (int r = 0; r <= n; ++r) {
            auto it = b.rbegin();
            for (auto& it : b) {
                int l = it.second;
                ll res = sqr(s[r]) - 2 * s[r] * s[l] + sqr(s[l]) - q[r] + q[l];
                chmax(answer, res);
            }
            b.insert(make_pair(sqr(s[r]) + q[r], r));
            while ((int)b.size() >= max_iter) {
                b.erase(b.begin());
            }
        }
        cout << answer / 2 << endl;
    }

    cerr << "Time execute: " << clock() / (double)CLOCKS_PER_SEC << " sec" << endl;
    return 0;
}