#include <bits/stdc++.h>
#define FAST ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);cerr.tie(0)
#define mp make_pair
#define xx first
#define yy second
#define pb push_back
#define pf push_front
#define popb pop_back
#define popf pop_front
#define all(x) x.begin(),x.end()
#define ff(i,a,b) for (int i = a; i < b; i++)
#define fff(i,a,b) for (int i = a; i <= b; i++)
#define bff(i,a,b) for (int i = b-1; i >= a; i--)
#define bfff(i,a,b) for (int i = b; i >= a; i--)
using namespace std;
long double typedef ld;
unsigned int typedef ui;
long long int typedef li;
pair<int,int> typedef pii;
pair<li,li> typedef pli;
pair<ld,ld> typedef pld;
vector<vector<int>> typedef graph;
unsigned long long int typedef ull;
//const int mod = 998244353;
const int mod = 1000000007;
//Note to self: Check for overflow
int n;
int v[500005];
int pre[500005];
int sum(int l, int r)
{
if (r==0) r=n;
if (l>r) return sum(1,r)+sum(l,n);
return pre[r]-pre[l-1];
}
int main()
{
FAST;
cin>>n;
fff(i,1,n) cin>>v[i];
fff(i,1,n) pre[i]=pre[i-1]+v[i];
int m=(n+1)/2;
vector<int> pole;
fff(i,1,n) pole.pb(sum(i,(i+m-1)%n));
multiset<int> sta;
ff(i,0,m) sta.insert(pole[i]);
int ans=*sta.begin();
ff(i,m,n+m)
{
sta.erase(sta.find(pole[i-m]));
sta.insert(pole[i%n]);
ans=max(ans,*sta.begin());
}
cout<<ans<<"\n";
}
//Note to self: Check for overflow
