#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int maxn = 5e5+5;
int n;
int v[2*maxn];
int pre[2*maxn];
struct MaxQueue
{
deque<pair<ll,int>> q;
int cnt_added = 0;
int cnt_removed = 0;
ll maximum() {
assert(!q.empty());
return q.front().first;
}
void push(ll new_element) { //add new element
while (!q.empty() && q.back().first < new_element) {
q.pop_back();
}
q.push_back({new_element,cnt_added});
cnt_added++;
}
void pop() {
if (!q.empty() && q.front().second == cnt_removed) {
q.pop_front();
}
cnt_removed++;
}
};
int main()
{
ios_base::sync_with_stdio(false); cin.tie(NULL);
cin >> n;
for (int i = 0; i < n; i++) {
cin >> v[i];
v[i+n] = v[i];
}
pre[0] = v[0];
for (int i = 1; i < 2*n; i++) {
pre[i] = pre[i-1] + v[i];
}
int total = pre[n-1];
MaxQueue mq;
for (int i = n/2; i < n-1; i++) {
mq.push(pre[i]-pre[i-n/2]);
}
int res = 0;
for (int i = 0; i < n; i++) {
mq.push(pre[i+n-1]-pre[i+n-1-n/2]);
int maxSum = mq.maximum();
res = max(res,total-maxSum);
mq.pop();
}
cout << res << '\n';
}
