#include "bits/stdc++.h"
using namespace std;
const int MAXN = 3e6;
const int INF = 1e9;
int n,N;
vector<int> tr;
void build(int n){
N = (1<<(32-__builtin_clz(n)));
tr.assign(2*N,INF);
}
void upd(int l, int r, int val){
if(l >= n) upd(l-n,r-n,val);
else if(r > n) {
upd(l,n,val);
upd(0,r-n,val);
} else {
for(l += N, r += N; l < r; l >>= 1, r >>= 1){
if(l&1) {
tr[l] = min(tr[l],val);
l++;
}
if(r&1) {
--r;
tr[r] = min(tr[r],val);
}
}
}
}
int get(int idx){
int ans = INF;
for(idx += N; idx > 0; idx >>= 1) ans = min(tr[idx],ans);
return ans;
}
int main(){
cin >> n;
vector<int> v(2*n);
for(int i = 0,x; i < n; ++i){
cin >> x;
v[i] = v[i+n] = x;
}
build(n);
int sum = 0;
int need = (n+1)/2;
for(int i = 0; i < 2*n; ++i){
sum += v[i];
if(i-need+1 >= 0) {
upd(i-need+1,i+1,sum);
sum -= v[i-need+1];
}
}
int res = 0;
for(int i = 0; i < n; ++i) res = max(res,get(i));
cout << res;
}
