#include <bits/stdc++.h>
using namespace std;
int main() {
cin.tie(0)->sync_with_stdio(0);
int n, sum=0, ans=1e9;
cin >> n;
vector<int> arr(n+2, 0), pf(2*n+2, 0), p(2*n+2, 0);
for(int i=1; i<=n; i++) {
cin >> arr[i];
sum += arr[i];
}
for(int i=1; i<=2*n; i++) {
if(i <= n) pf[i] = pf[i-1] + arr[i];
else pf[i] = pf[i-1] + arr[i-n];
}
for(int i=1; i<=n+n/2; i++) {
p[i] = pf[i+n/2-1] - pf[i-1];
}
multiset<int> s;
for(int i=1; i<=n/2; i++) {
s.insert(p[i]);
}
ans = min(ans, *s.rbegin());
for(int i=2; i<=n; i++) {
s.erase(s.find(p[i-1]));
s.insert(p[i+n/2-1]);
ans = min(ans, *s.rbegin());
}
cout << sum-ans;
}
