#include "bits/stdc++.h"
using namespace std;
void abc() {cout << endl;}
template <typename T, typename ...U> void abc(T a, U ...b) {
cout << a << ' ', abc(b...);
}
template <typename T> void printv(T l, T r) {
while (l != r) cout << *l << " \n"[++l == r];
}
template <typename A, typename B> istream& operator >> (istream& o, pair<A, B> &a) {
return o >> a.first >> a.second;
}
template <typename A, typename B> ostream& operator << (ostream& o, pair<A, B> a) {
return o << '(' << a.first << ", " << a.second << ')';
}
template <typename T> ostream& operator << (ostream& o, vector<T> a) {
bool is = false;
for (T i : a) {o << (is ? ' ' : '{'), is = true, o << i;}
return o << '}';
}
#ifdef local
#define test(args...) abc("[" + string(#args) + "]", args)
#else
#define test(args...) void(0)
#endif
using ll = long long;
int v[500005];
int cycle[500005];
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
// freopen("", "r", stdin);
// freopen("", "w", stdout);
int n; cin >> n;
for (int i = 0; i < n; i++) {
cin >> v[i];
}
int needed = ceil(n / 2.0);
int total = 0;
for (int i = 0; i < needed; i++) {
total += v[i];
}
cycle[0] = total;
for (int i = 1; i < n; i++) {
total -= v[i - 1];
total += v[(i + needed - 1) % n];
cycle[i] = total;
}
multiset<int> calc;
for (int i = 0; i < needed; i++) {
calc.insert(cycle[i]);
}
int ans = *calc.begin();
for (int i = 1; i < n; i++) {
calc.erase(calc.find(cycle[ i - 1]));
calc.insert(cycle[( i + needed - 1) % n]);
ans = max(ans, *calc.begin());
}
cout << ans << endl;
}
