#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
int n;
ll a[(1<<18)+1];
const int d=18;
ll dp[37][100010];
ll solve(int s, int x){
    if(x>n) return 0;
    if(dp[s+d][x]>=0) return dp[s+d][x];
    ll s1=solve(s+1, 2*x)+a[2*x]*(s+1), s2=solve(s-1, 2*x+1)+a[2*x+1]*(s-1);
    ll s3=solve(s-1, 2*x)+a[2*x]*(s-1), s4=solve(s+1, 2*x+1)+a[2*x+1]*(s+1);
    ll ans=max({0ll, s1, s1+s2, s1, s3+s4, s4});
    return dp[s+d][x]=ans;
}
int main()
{
    cin>>n;
    for(int i=1; i<=n; i++) cin>>a[i];
    for(int i=1; i<=n; i++) for(int j=0; j<=2*d; j++) dp[j][i]=-1;
    cout<<solve(0, 1)<<endl;
    return 0;
}