#include <bits/stdc++.h>
using namespace std;
int n;
vector<int> vals;
class ST {
int n;
vector<int> val;
public:
ST(vector<int> _val) {
val = _val;
n = _val.size() / 2;
for (int i = n - 1; i > 0; i--)
val[i] = min(val[(i << 1)], val[1 | (i << 1)]);
}
int query(int l, int r) {
if (n < r) {
r -= n;
return min(query(0, r + 1), query(l, n));
}
int ans = 1e9;
for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
if (l & 1)
ans = min(ans, val[l++]);
if (r & 1)
ans = min(ans, val[--r]);
}
return ans;
}
};
int main() {
cin >> n;
vals.resize(n);
for (int i = 0; i < n; i++)
cin >> vals[i];
int rollsum = 0;
int sz = (n + 1) / 2;
for (int i = 0; i < sz; i++) {
rollsum += vals[i];
}
vector<int> val(n * 2, 1e9);
for (int i = 0; i < n; i++) {
val[n + i] = rollsum;
rollsum += vals[(i + n / 2) % n] - vals[i % n];
}
ST st(val);
int ans = 0;
for (int i = 0; i < n; i++) {
int res = st.query(i, i + sz);
ans = max(res, ans);
}
cout << ans << endl;
return 0;
}
