import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }




void main() {
  try {
    for (; ; ) {
      const N = readInt();
      auto A = new long[N + 1];
      foreach (u; 1 .. N + 1) {
        A[u] = readLong();
      }
      
      auto dep = new int[N + 1];
      dep[1] = 0;
      foreach (u; 2 .. N + 1) {
        dep[u] = dep[u >> 1] + 1;
      }
      
      auto dp = new long[][N + 1];
      foreach_reverse (u; 1 .. N + 1) {
        const uL = u << 1;
        const uR = u << 1 | 1;
        dp[u] = new long[dep[u] + 1 + dep[u]];
        foreach (k; -dep[u] .. +dep[u] + 1) {
          foreach (s; [+1, -1]) {
            long cost = k * A[u];
            if (uL <= N) {
              cost += dp[uL][dep[uL] + k + s];
            }
            if (uR <= N) {
              cost += dp[uR][dep[uR] + k - s];
            }
            chmax(dp[u][dep[u] + k], cost);
          }
        }
      }
      writeln(dp[1][0]);
    }
  } catch (EOFException e) {
  }
}