#include <bits/stdc++.h>
using std::deque;
using std::pair;
using std::vector;
class SlidingMinimum {
int push_i, pop_i;
deque<pair<int, int>> deq;
public:
SlidingMinimum() : push_i(0), pop_i(0), deq() {}
void push(const int x) {
while (!deq.empty() and deq.back().first >= x) {
deq.pop_back();
}
deq.emplace_back(x, push_i++);
}
void pop() {
if (deq.front().second == pop_i) {
deq.pop_front();
}
pop_i += 1;
}
int min() const { return deq.front().first; }
};
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
int N;
std::cin >> N;
vector<int> V(N);
for (auto& x : V) {
std::cin >> x;
}
vector<int> sum(2 * N + 1);
for (int i = 0; i < N; ++i) {
sum[i + 1] = sum[i] + V[i];
}
for (int i = 0; i < N; ++i) {
sum[i + N + 1] = sum[i + N] + V[i];
}
const int len = (N + 1) / 2;
vector<int> take(N);
for (int i = 0; i < N; ++i) {
take[i] = sum[i + len] - sum[i];
}
SlidingMinimum window;
for (int i = N - len; i < N; ++i) {
window.push(take[i]);
}
int ans = 0;
for (int i = 0; i < N; ++i) {
window.pop();
window.push(take[i]);
ans = std::max(ans, window.min());
}
std::cout << ans << '\n';
return 0;
}
