#include <bits/stdc++.h>
using namespace std;
inline namespace
{
} // namespace
void solve(const int _test_ = -1)
{
int n;
cin >> n;
int m = (n + 1) / 2;
vector<long> v(n);
for (long &x : v)
cin >> x;
vector w = v;
for (int i = 0; i < m; i++)
w.push_back(v[i]);
long res = 0;
multiset<long> ms;
queue<long> q;
long sum = 0;
for (int i = n - m; i < n; i++)
sum += w[i];
for (int i = n - m; i < n; i++)
{
sum += w[i + m] - w[i];
q.push(sum);
ms.insert(sum);
}
for (int i = 0; i < n; i++)
{
ms.erase(ms.find(q.front()));
q.pop();
sum += w[i + m] - w[i];
q.push(sum);
ms.insert(sum);
res = max(res, *ms.begin());
}
cout << res << '\n';
}
int main()
{
ios_base::sync_with_stdio(false), cin.tie(NULL);
int T_ = 1;
// cin >> T_;
for (int t_ = 0; t_ < T_; t_++)
solve(t_);
return 0;
}
