#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 5e5 + 5;
int n;
int arr[MAX_N];
int segtree[4 * MAX_N];
void update(int i, int x, int u = 1, int lo = 1, int hi = n) {
if (lo == hi) {
segtree[u] = x;
return;
}
int mid = (lo + hi) / 2;
if (i <= mid)
update(i, x, 2 * u, lo, mid);
else
update(i, x, 2 * u + 1, mid + 1, hi);
segtree[u] = max(segtree[2 * u], segtree[2 * u + 1]);
}
int query(int l, int r, int u = 1, int lo = 1, int hi = n) {
if (l <= lo && hi <= r)
return segtree[u];
int mid = (lo + hi) / 2, ans = 0; // arr[i] >= 1
if (l <= mid)
ans = max(ans, query(l, r, 2 * u, lo, mid));
if (r > mid)
ans = max(ans, query(l, r, 2 * u + 1, mid + 1, hi));
return ans;
}
int subarray_sum[MAX_N];
int tot_sum;
void precomp() {
int s = n / 2;
for (int i = 1; i <= s; i++)
subarray_sum[1] += arr[i];
for (int i = 2; i <= n; i++) {
int j = i + s - 1;
if (j > n)
j -= n;
subarray_sum[i] = subarray_sum[i - 1] - arr[i - 1] + arr[j];
// cout << subarray_sum[i] << " ";
}
for (int i = 1; i <= n; i++)
update(i, subarray_sum[i]);
for (int i = 1; i <= n; i++)
tot_sum += arr[i];
}
int main() {
// freopen("hacker.in", "r", stdin);
cin >> n;
for (int i = 1; i <= n; i++)
cin >> arr[i];
precomp();
int s = n / 2;
int ans = 0;
for (int i = 1; i <= n; i++) {
int j = i - s;
if (j >= 1)
ans = max(ans, tot_sum - max(query(i + 1, n), query(1, j)));
else {
j += n;
ans = max(ans, tot_sum - query(i + 1, j));
}
}
cout << ans << '\n';
}
