#include <bits/stdc++.h>
#define f first
#define s second
#define int long long
using namespace std;
const int N = 1e6 + 69;
int n, a[N], p[N], c[N];
signed main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int tt = 1;
//cin >> tt;
while (tt--) {
cin >> n;
for (int i = 1;i <= n;i++)
cin >> a[i];
for (int i = n + 1;i <= 2 * n;i++)
a[i] = a[i - n];
int all = 0;
for (int i = 1;i <= n;i++)
all += a[i];
for (int i = 1;i <= 2 * n;i++)
p[i] = p[i - 1] + a[i];
auto Get = [&](int l, int r) {
if (l > r)
return p[n] - p[l - 1] + p[r];
return p[r] - p[l - 1];
};
int k = (n + 1) / 2, ans = 0;
for (int i = 1;i <= n;i++) {
int j = i - k + 1;
if (j <= 0)
j += n;
c[i] = Get(j, i);
}
deque<pair<int, int>> st;
for (int i = n - k + 2;i <= n;i++) {
while (!st.empty() && st.back().s >= c[i])
st.pop_back();
st.push_back({i, c[i]});
}
for (int i = 1;i <= n;i++) {
while (!st.empty() && st.back().s >= c[i])
st.pop_back();
st.push_back({i, c[i]});
ans = max(ans, st.front().s);
int j = i - k + 1;
if (j <= 0)
j += n;
if (st.front().f == j)
st.pop_front();
}
cout << ans << '\n';
}
return 0;
}
