#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pp;
#define rep(i,l,r) for(int i = (l); i < (r); (i)++)
#define per(i,r,l) for(int i = (r); i >= (l); (i)--)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()
#define pb push_back
#define ff first
#define ss second
// #include <ext/pb_ds/assoc_container.hpp>
// using namespace __gnu_pbds;
// template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const ll mod = 1e9 + 7, maxn = 2e5 + 5, inf = 1e18 + 5;
int main(){
cin.tie(0) -> sync_with_stdio(0);
int n; cin >> n;
vector<ll> v(n), s(n);
ll su = 0;
rep(i,0,n){
cin >> v[i];
su += v[i];
}
int t = n/2;
ll sum = 0;
rep(i,0,t){
sum += v[i];
}
s[0] = sum;
rep(i,1,n){
sum += v[(i + t - 1)%n];
sum -= v[i - 1];
s[i] = sum;
}
ll ans = inf;
deque<int> q;
rep(i,1,n){
if(i + t - 1 >= n) break;
while(sz(q) && s[q.back()] < s[i]) q.pop_back();
q.pb(i);
}
ans = min(ans, s[q.front()]);
rep(i,1,n){
if(q.front() == i) q.pop_front();
while(sz(q) && s[q.back()] < s[(i - t + n)%n]) q.pop_back();
q.pb((i - t + n)%n);
ans = min(ans, s[q.front()]);
}
cout << su - ans;
return 0;
}
