#include <bits/stdc++.h>
using namespace std;
signed main() {
ios_base::sync_with_stdio(false); cin.tie(nullptr);
int n; cin >> n;
vector<int> v(n*2+(n/2)+1,0);
vector<int> mx(n*2+(n/2)+1,0);
int tot=0;
for (int i = 0; i < n; i++) {
cin >> v[i];
tot+=v[i];
}
for (int i = 0; i <= n; i++) v[i+n]=v[i];
for (int i = 0; i < n*2; i++) v[i]+=v[i-1];
int sum=0;
for (int i = 0; i <= (n-1)/2; i++) sum+=v[i];
mx[0]=sum;
int half=((n+1)/2);
for (int i = 0; i < n*2; i++){
mx[i]=v[i+half-1]-v[i-1];
}
for (int i = 0; i <= n; i++) mx[i+n]=mx[i];
deque<int> queue;
for (int i = 0; i < half; i++)
{
while(!queue.empty()&&mx[queue.back()]>mx[i]) queue.pop_back();
queue.push_back(i);
}
int outp=mx[queue.front()];
for (int i = half; i < (n*2); i++)
{
if(!queue.empty()&&queue.front()==i-half) queue.pop_front();
while(!queue.empty()&&mx[queue.back()]>mx[i]) queue.pop_back();
queue.push_back(i);
outp=max(mx[queue.front()], outp);
}
cout << outp << "\n";
return 0;
}
