#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
#define endl '\n'
#define ll long long
#define pi pair<int, int>
#define f first
#define s second
const int mxn = 1000001;
int n;
ll a[mxn];
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n;
for(int i = 1; i <= n; i++){
cin >> a[i];
a[n + i] = a[i];
a[i] += a[i - 1];
}
ll ret = 0, ret2 = 0;
for(int i = n + 1; i <= 2 * n; i++){
a[i] += a[i - 1];
ret2 = max(ret2, a[i] - a[i - (n + 1) / 2]);
if(ret2 > ret) swap(ret, ret2);
}
cout << ret2 << endl;
return 0;
}
