/* IN THE NAME OF GOD */
/* |\/| /-\ |\| | |\/| /-\ */
#include "bits/stdc++.h"
using namespace std;
#define sz(x) (int)x.size()
#define endl '\n'
#define pb push_back
#define all(x) x.begin(), x.end()
#define F first
#define S second
#define mr make_pair
//#define int long long
#define pii pair<int, int>
typedef long double ld;
typedef long long ll;
mt19937 rng (chrono::high_resolution_clock::now().time_since_epoch().count());
const int N = 5e5 + 10;
const int MOD = 1e9 + 7;
const int inf = 1e9 + 1;
const ll INF = 3e18;
int a[N], ps[N], seg[N * 4], lz[N * 4];
void shift(int id, int s, int e){
if(s == e)
return;
seg[id * 2] = min(seg[id * 2], lz[id]);
seg[id * 2 + 1] = min(seg[id * 2 + 1], lz[id]);
lz[id * 2] = min(lz[id], lz[id * 2]);
lz[id * 2 + 1] = min(lz[id], lz[id * 2 + 1]);
}
void upd(int id, int s, int e, int l, int r, int x){
shift(id, s, e);
if(s > r || e < l)
return;
if(l <= s && e <= r){
seg[id] = min(seg[id], x);
lz[id] = min(lz[id], x);
return;
}
int mid = (s + e) / 2;
upd(id * 2, s, mid, l, r, x);
upd(id * 2 + 1, mid + 1, e, l, r, x);
seg[id] = min(seg[id * 2], seg[id * 2 + 1]);
}
int get(int id, int s, int e, int p){
shift(id, s, e);
if(s > p || e < p)
return inf;
if(s == e && e == p)
return seg[id];
int mid = (s + e) / 2;
return min(get(id * 2, s, mid, p), get(id * 2 + 1, mid + 1, e, p));
}
int32_t main(){
ios_base:: sync_with_stdio(0), cin.tie(0), cout.tie(0);
int n;
cin >> n;
int t = n / 2 + (n % 2);
for(int i = 1; i < 4 * N; i++){
seg[i] = inf;
lz[i] = inf;
}
for(int i = 1; i <= n; i++){
cin >> a[i];
ps[i] = ps[i - 1] + a[i];
}
for(int i = 1; i <= n; i++){
if(i >= t)
upd(1, 1, n, i - t + 1, i, ps[i] - ps[i - t]);
else{
upd(1, 1, n, 1, i, ps[i] + ps[n] - ps[n - (t - i)]);
upd(1, 1, n, n - (t - i) + 1, n, ps[i] + ps[n] - ps[n - (t - i)]);
}
}
int ans = 0;
for(int i = 1; i <= n; i++)
ans = max(ans, get(1, 1, n, i));
cout << ans << endl;
}
