#include <bits/stdc++.h>
#include <experimental/random>
#include <random>
//#include <ext/pb_ds/assoc_container.hpp>
//using namespace __gnu_pbds;
using namespace std;
using ld = long double;
using ll = long long;
const ll INF = 1e18, MOD = 1e9 + 7;
void solve();
signed main() {
#ifdef LOCAL
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
ios::sync_with_stdio(false);
cin.tie(0);
int q = 1;
//cin >> q;
while (q--) {
solve();
}
}
void solve() {
ll n; cin >> n;
vector<ll> a(n);
for (int i = 0; i < n; i++) cin >> a[i];
for (int i = 0; i < n; i++) a.push_back(a[i]);
ll l = 0, r = INF;
while (r - l > 1) {
ll mid = (l + r) / 2;
if (mid == 10) {
ll t = 1;
}
vector<ll> next(2 * n, INF);
ll sm = 0, id = 0;
for (int i = 0; i < 2 * n; i++) {
while (id < 2 * n && sm < mid) {
sm += a[id++];
}
if (sm >= mid) next[i] = id;
sm -= a[i];
}
bool flag = false;
for (int i = 0; i < 2 * n; i++) {
if (next[i] >= 2 * n || next[next[i]] >= 2 * n || next[next[next[i]]] == INF) continue;
if (next[next[next[i]]] - i <= n) flag = true;
}
if (flag) {
l = mid;
} else {
r = mid;
}
}
cout << l;
}
