#include <bits/stdc++.h>
using namespace std;
#define forsn(i, s, n) for (int i = int(s); i < int(n); i++)
#define forn(i, n) forsn(i, 0, n)
#define dforsn(i, s, n) for (int i = int(n) - 1; i >= int(s); i--)
#define dforn(i, n) dforsn(i, 0, n)
#define qforn(i, n) for (i = 0; i < n; i++)
using vi = vector<int>;
using ii = pair<int, int>;
using vii = vector<ii>;
using ll = long long;
using ld = long double;
using vll = vector<ll>;
using vb = vector<bool>;
using pll = pair<ll, ll>;
#define sz(x) int(x.size())
#define all(x) begin(x), end(x)
#define pb push_back
#define eb emplace_back
#define fst first
#define snd second
int main() {
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n;
cin >> n;
vll a(2 * n);
forn(i, n) cin >> a[i], a[i + n] = a[i];
vll pref(2 * n + 1);
forn(i, 2 * n) pref[i + 1] = pref[i] + a[i];
auto find = [&](int i, ll k) {
int lo = i, hi = 2 * n + 1;
while (hi - lo > 1) {
int mid = (lo + hi) / 2;
if (pref[mid] - pref[i] < k) {
lo = mid;
} else {
hi = mid;
}
}
return hi;
};
auto checki = [&](int i, ll k) {
int j = find(i, k);
if (j > i + n) return false;
j = find(j, k);
if (j > i + n) return false;
j = find(j, k);
return j <= i + n;
};
auto check = [&](ll k) {
forn(i, n) if (checki(i, k)) return true;
return false;
};
ll lo = 0, hi = 1e15;
while (hi - lo > 1) {
ll mid = (lo + hi) / 2;
if (check(mid)) lo = mid;
else hi = mid;
}
cout << lo << "\n";
return 0;
}
