/*
File created on 06/14/2021 at 12:41:02.
Link to problem:
Description:
Time complexity: O()
Space complexity: O()
Status: DEV
Copyright: Ⓒ 2021 Francois Vogel
*/
#include <iostream>
#include <cmath>
#include <vector>
#include <bitset>
#include <queue>
#include <cstring>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <algorithm>
using namespace std;
#define pii pair<int, int>
#define f first
#define s second
#define pb push_back
#define ins insert
#define cls clear
#define ll long long
const int p2 = 1<<20;
const int inf = 1e9;
int bt [p2*2];
void btCls() { for (int i = 0; i < p2*2; i++) bt[i] = inf; }
void btUpd(int rb, int re, int rv, int qn = 1, int qb = 0, int qe = p2-1) {
if (rb > qe or qb > re) return;
else if (rb <= qb and qe <= re) bt[qn] = min(bt[qn], rv);
else {
int qm = (qb+qe)/2;
btUpd(rb, re, rv, qn*2, qb, qm);
btUpd(rb, re, rv, qn*2+1, qm+1, qe);
}
}
int btGet(int idx) {
int mnv = inf;
for (idx += p2; idx != 0; idx /= 2) mnv = min(mnv, bt[idx]);
return mnv;
}
signed main() {
cin.tie(0);
// ios_base::sync_with_stdio(0);
int n;
cin >> n;
int b [n];
for (int i = 0; i < n; i++) cin >> b[i];
btCls();
int divS = (n+1)/2;
int curSum = 0;
for (int i = 0; i < divS; i++) curSum += b[i];
for (int i = 0; i < n; i++) {
int start = i;
int end = (i+divS-1)%n;
if (start < end) {
btUpd(start, end, curSum);
}
else {
btUpd(start, n-1, curSum);
btUpd(0, end, curSum);
}
curSum -= b[i];
curSum += b[(i+divS)%n];
}
int mxv = 0;
for (int i = 0; i < n; i++) {
mxv = max(mxv, btGet(i));
}
cout << mxv;
int d = 0;
d++;
}
