#include <bits/stdc++.h>

using namespace std;

#define int long long
#define ll long long
#define forn(i, n) for (ll i = 0; i < n; ++i)
#define forr(i, s, n) for (ll i = s; i < n; ++i)
#define fori(i, s, n) for (ll i = s; i > n; --i)
#define fora(i, n) for (auto i: n)
#define vi vector<int>
#define vll vector<ll>
#define prints(n) cout << (n) << " "
#define println(n) cout << (n) << "\n"
#define newl() cout << "\n"

const int MOD = 998244353;
// const int MOD = 1e9 + 7;

void solve() {
    ll n; cin >> n;
    vector<ll> a(n); fora(&x, a) cin >> x;
    vector<ll> suf(n + 1), pre(n + 1);

    fori(i, n - 1, -1) suf[i] = suf[i + 1] + a[i];
    forn(i, n) pre[i + 1] = pre[i] + a[i];

    // fora(x, suf) prints(x); newl();
    // fora(x, pre) prints(x); newl();

    vector<pair<ll, ll>> v = {{0, a[0]}};
    ll ans = max(a[0], suf[1]);

    ll mn = a[0];
    forr(i, 1, n) {
        mn += a[i];
        v.push_back({i, v.back().second + a[i]});

        fora(x, v) {
            if (pre[i + 1] - pre[x.first + 1] >= x.second) {
                v.push_back({i, pre[i + 1] - pre[x.first + 1]});
                mn = min(mn, pre[i + 1] - pre[x.first + 1]);
                ans = min(ans, max(v.back().second, suf[i + 1]));
            }
        }

        // println(i);
        // fora(x, v) {
        //     prints(x.first); println(x.second);
        // }

        // println(mn);
        fori(j, v.size() - 1, -1) {
            // prints(j); println(pre[i + 1] - pre[v[j].first + 1] + v[j].second);
            // prints(pre[i + 1]); prints(pre[v[j].first + 1]); println(v[j].second);
            if (pre[i + 1] - pre[v[j].first + 1] + v[j].second > mn) {
                // println("ERASED");
                v.erase(begin(v) + j);
            }
        }

        // println(i);
        // fora(x, v) {
        //     prints(x.first); println(x.second);
        // }
    }

    println(ans);
}

int32_t main() {
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    int t = 1;
    // cin >> t;
    while (t--) solve();

    return 0;
}