#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx")
#include <bits/stdc++.h>

using std::cerr;
using std::cin;
using std::cout;

using std::abs;
using std::min;
using std::max;
using std::swap;

using std::map;
using std::pair;
using std::set;
using std::string;
using std::vector;

using ll = long long;
using uint = unsigned int;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

#define ff first
#define ss second
#define pb emplace_back
template<typename T> 
void _dbg(const char* _s, T _h) {
    cerr << _s << " = " << _h <<"\n"; 
}
template<typename T, typename... Ts>
void _dbg(const char* _s, T _h, Ts... _t) {
    int _b = 0;
    while (((_b += *_s == '(') -= *_s == ')') != 0 || *_s != ',')
        cerr << *_s++; 
    cerr << " = " << _h << ","; 
    _dbg(_s+1, _t...);
}
#ifdef LOCAL
#define dbg(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#else
#define dbg(...) 
#endif

struct init {
    init() {
        cin.tie(0);
        std::iostream::sync_with_stdio(0);
        cout << std::fixed << std::setprecision(10);
        cerr << std::fixed << std::setprecision(5);
        #ifdef LOCAL
        srand(300); 
        #else
        using namespace std::chrono;
        srand(duration_cast<nanoseconds>(high_resolution_clock::now().time_since_epoch()).count()); 
        #endif
    }
    ~init() {
        #ifdef LOCAL
        cerr << "Time elapsed: " << (double)clock() / CLOCKS_PER_SEC << "s.\n";
        #endif
    }
} init;

const int MAXN = 2e5 + 15;
ll a[MAXN];
ll aq[MAXN];
ll p[MAXN];
ll pq[MAXN];
int main() {

    int n;
    cin >> n;
    for (int i = 1; i <= n; ++i) {
        cin >> a[i];
        p[i] = p[i - 1] + a[i];
        aq[i] = a[i] * a[i];
        pq[i] = pq[i - 1] + aq[i];
    }   

    ll ans = 0;
    for (int l = 1; l <= n; ++l)
        for (int r = l; r <= n; ++r) {
            ll pot = (p[r] - p[l - 1]) * (p[r] - p[l - 1]) - pq[r] + pq[l - 1];
            if (ans < pot)
                ans = pot;
        }

    cout << ans/2 << '\n';



    return 0;
}