//{
#include <iostream>
#include <iomanip>
#include <vector>
#include <array>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <algorithm>
#include <cmath>
#include <numeric>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
#include <climits>
#include <bitset>
//}
using namespace std;
typedef long long ll;
void solve () {
ll n; cin >> n;
vector<ll> a(2 * n + 1);
ll sz = (n + 1) / 2;
for (ll i = 1; i <= n; i++) {
cin >> a[i];
a[n + i] = a[i];
}
for (ll i = 1; i <= 2 * n; i++) {
a[i] += a[i - 1];
}
vector<ll> v(n + 1, 1e18);
multiset<ll> st;
for (ll i = 1; i <= 2 * n; i++) {
if (i + sz - 1 <= 2 * n) {
st.insert(a[i + sz - 1] - a[i - 1]);
}
if (i > sz) {
st.erase(st.find(a[i - 1] - a[i - sz - 1]));
}
ll prev = ((i - 1) % n) + 1;
v[prev] = min(v[prev], *st.begin());
}
ll ans = 0;
for (ll i = 1; i <= n; i++) {
ans = max(ans, v[i]);
}
cout << ans;
}
int main() {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int t = 1; //cin >> t;
while (t--) solve();
}
