#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
const int INF = 0x3f3f3f3f;
const ll LINF = 0x3f3f3f3f3f3f3f3fLL;
const double EPS = 1e-8;
const int MOD = 1000000007;
// const int MOD = 998244353;
const int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
const int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  const int X = 15;
  int n; cin >> n;
  vector<int> a(n); REP(i, n) cin >> a[i];
  vector dp(n, vector(X * 2 + 1, -LINF));
  function<ll(int, int)> rec = [&](int i, int j) {
    if (i >= n) return 0LL;
    if (dp[i][j] != -LINF) return dp[i][j];
    int l = i * 2 + 1, r = i * 2 + 2;
    return dp[i][j] = max({rec(l, j + 1) + rec(r, j - 1), rec(l, j - 1) + rec(r, j + 1), rec(l, j + 1), rec(r, j + 1), 0LL}) + 1LL * (j - X) * a[i];
  };
  cout << rec(0, X) << '\n';
  return 0;
}