#include <iostream> //#define int __int128 using namespace std; int n; int cnt[100005], a[100005]; //istream& operator>>(istream& in, int &x) {long long y; in >> y; x = y; return in;}ostream& operator<<(ostream& out, int x) {string s;while (x) {s = char(x % 10 ^ 48) + s, x /= 10; out << s; return out;} signed main() { cin >> n; for (int i = 1; i <= n; i++) { cin >> a[i]; cnt[i] = a[i] + cnt[i - 1]; } int ans(cnt[n]); for (int i = 1; i < n; i++) { ans = max(ans, cnt[n] - a[i] - a[i + 1] + a[i] * a[i + 1]); } ans = max(ans, cnt[n] - a[1] - a[n] + a[1] * a[n]); cout << ans; }