#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N=(int)5e5;
LL sum[N*2+2]={},a[N*2+2]={};
int n;
int main(){
ios::sync_with_stdio(false);
cin.tie(0) ; cout.tie(0);
// freopen("main.inp","r",stdin);
cin>>n;
int slide=(n+1)/2;
for(int i=1;i<=n;++i) cin>>a[i];
for(int i=n+1;i<=n*2;++i) a[i]=a[i-n];
for(int i=1;i<=n*2;++i) sum[i]=sum[i-1]+a[i];
for(int i=1;i<=n;++i) a[i]=sum[i+slide-1]-sum[i-1];
for(int i=n+1;i<=n*2;++i) a[i]=a[i-n];
deque<int>q;
for(int i=1;i<=n;++i){
while (q.size() && a[q.back()]>=a[i]) q.pop_back();
q.push_back(i);
}
LL ans=0;
for(int i=n+1;i<=n*2;++i){
while (q.size() && q.front() < i-slide+1) q.pop_front();
while (q.size() && a[q.back()] >= a[i]) q.pop_back();
q.push_back(i);
ans=max(ans,a[q.front()]);
}
cout<<ans;
}
