/*
Author: Nguyen Chi Thanh - High School for the Gifted - VNU.HCM (i2528)
*/
#include <bits/stdc++.h>
using namespace std;
/* START OF TEMPALTE */
#define int long long
#define ll long long
#define ull unsigned long long
#define ld long double
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second
#define popcount __builtin_popcountll
#define all(x) (x).begin(), (x).end()
#define BIT(x, i) (((x) >> (i)) & 1)
#define MASK(x) (1ll << (x))
#define SZ(a) ((int32_t)a.size())
#define debug(a, l, r) {for (int _i = (l); _i <= (r); ++_i) cout << (a)[_i] << ' '; cout << '\n';}
template<class X, class Y>
bool minimize(X &x, const Y &y) {
if (x > y) {
x = y;
return true;
} else return false;
}
template<class X, class Y>
bool maximize(X &x, const Y &y) {
if (x < y) {
x = y;
return true;
} else return false;
}
/* END OF TEMPALTE */
const int MAXN = 5e5 + 5;
const int INF = (int)1e9 + 7;
struct SegmentTree {
int n;
vector<int> seg;
SegmentTree (int _n) : n(_n), seg(4 * n + 5, INF) {}
void update(int id, int l, int r, int u, int v, int x) {
if (r < u || v < l) return;
if (u <= l && r <= v) {
minimize(seg[id], x);
return;
}
int mid = (l + r) >> 1;
update(id << 1, l, mid, u, v, x);
update(id << 1 | 1, mid + 1, r, u, v, x);
}
int get(int id, int l, int r, int pos) {
if (l == r) return seg[id];
int mid = (l + r) >> 1;
if (pos <= mid) return min(seg[id], get(id << 1, l, mid, pos));
else return min(seg[id], get(id << 1 | 1, mid + 1, r, pos));
}
void update(int u, int v, int x) {
update(1, 1, n, u, v, x);
}
int get(int pos) {return get(1, 1, n, pos);}
};
int n, a[2 * MAXN], pref[2 * MAXN];
void init() {
cin >> n;
for (int i = 1; i <= n; ++i) {
cin >> a[i];
a[i + n] = a[i];
}
for (int i = 1; i <= 2 * n; ++i)
pref[i] = pref[i - 1] + a[i];
}
// namespace brute {
// bool check() {
// return n <= 5000;
// }
// void solve() {
// int len = n / 2 + (n & 1);
// vector<int> mi(n + 5, INF);
// for (int i = 0; i < n; ++i) {
// int sum = 0;
// for (int j = 0; j < len; ++j)
// sum += a[(i + j) % n];
// for (int j = 0; j < len; ++j) {
// int cur = (i + j) % n;
// minimize(mi[cur], sum);
// }
// }
// int res = -INF;
// for (int i = 0; i < n; ++i) maximize(res, mi[i]);
// cout << res;
// }
// }
void solve() {
int len = n / 2 + (n & 1);
SegmentTree seg(2 * n);
for (int i = 1; i <= 2 * n - len + 1; ++i) {
int j = i + len - 1;
int sum = pref[j] - pref[i - 1];
seg.update(i, j, sum);
}
int ans = -INF;
for (int i = 1; i <= n; ++i) {
int contrib = min(seg.get(i), seg.get(i + n));
maximize(ans, contrib);
}
cout << ans;
}
signed main() {
#ifdef NCTHANH
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
ios_base::sync_with_stdio(0);
cin.tie(nullptr); cout.tie(nullptr);
init();
// if (brute::check()) return brute::solve(), 0;
solve();
return 0;
}
