#include <bits/stdc++.h>
#define speed ios_base::sync_with_stdio(0); cin.tie(0)
#define all(x) (x).begin(),(x).end()
#define F first
#define S second
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx,avx2")
//#pragma GCC target("popcnt")
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const ll MAX=2e5+10,P=1e9+7;
const ll INF=0x3f3f3f3f,oo=0x3f3f3f3f3f3f3f3f;
const ldb eps=1e-6;
const ldb PI=acos(-1.0);
const int dir[4][2]={{0,1},{0,-1},{1,0},{-1,0}};
template<typename T>
using vvector = vector<vector<T>>;
int main() {
speed;
int n;
cin>>n;
vector<int> a(2*n+1);
vector<int> pre(2*n+1);
pre[0]=0;
for (int i=1;i<=n;i++) {
cin>>a[i];
a[i+n]=a[i];
}
for (int i=1;i<=2*n;i++) {
pre[i]=pre[i-1]+a[i];
}
set<pll> st;
int l = (n+1)/2;
for (int i=1;i<=l;i++) {
st.insert({pre[i+l-1]-pre[i-1],i});
}
ll ans=0;
for (int i=l;i<l+n;i++) {
ans=max(ans,st.begin()->F);
st.erase({pre[i]-pre[i-l],i-l+1});
st.insert({pre[i+l]-pre[i],i+1});
}
cout<<ans<<"\n";
return 0;
}
