//Segment Tree is a State of Mind
#include <bits/stdc++.h>
using namespace std;
#define debug(x) cerr<<#x<<" is "<<x<<endl;
#define debugl(x) cerr << #x << " is "; for(auto p : x) cerr << p << " "; cerr << endl;
#define debugpl(x) cerr<<#x<<" is ";for(auto p:x)cerr<<p.first<<" "<<p.second<<endl;cerr<<endl;
#define int long long
typedef vector<int> vi;
typedef pair<int,int> pii;
typedef pair<int,pii> ipii;
#define pb push_back
#define fi first
#define se second
#define sz(x) (int)(x).size()
int inf=4e18+5;
int mod=1e9+7;
signed main(){
ios_base::sync_with_stdio(0);cin.tie(0);
//mt19937_64 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
int n;cin>>n;
int a[2*n];
int t=0;
for(int i=0;i<n;i++){
cin>>a[i];
t+=a[i];
a[i+n]=a[i];
}
deque<int> dq;
multiset<int> s;
int w=n/2;
int cs=0,ans=0;
for(int i=1;i<1+w;i++){
cs+=a[i];
}
dq.pb(cs);
s.insert(cs);
int l=1;
for(int r=1+w;r<n;r++){
cs+=a[r];
cs-=a[l];
dq.pb(cs);
s.insert(cs);
l++;
}
//debugl(dq)
ans=t-(*(--s.end()));
//debug(ans)
for(int r=n;r<2*n;r++){
int old=dq.front();
s.erase(s.find(old));
dq.pop_front();
cs+=a[r];
cs-=a[l];
l++;
dq.pb(cs);
s.insert(cs);
//debugl(dq)
ans=max(ans,t-(*(--s.end())));
//debug(ans)
}
cout<<ans<<'\n';
}
