#include<bits/stdc++.h>
using namespace std;

int n,a[100001],val[100001],ans;

void solve(int u,int x)
{
    switch(u)
    {
    case 0:
        x=0;
        break;
    case 1:
    case 2:
        x=15;
        break;
    case 3:
    case 4:
        --x;
        break;
    case 6:
        ++x;
        break;
    case 7:
        x+=3;
        break;
    }
    if(x==0||(2*u>n))
        return;
    ++val[u];
    val[2*u]=val[2*u+1]=val[u];
    solve(2*u,x);
    solve(2*u+1,x);
}

int main()
{
    freopen("traversal.in","r",stdin);
    freopen("traversal.out","w",stdout);
    cin>>n;
    for(int i=1;i<=n;i++)
        cin>>a[i];
    solve(1,0);
    for(int i=1;i<=n;i++)
        ans=max(ans,val[i]);
    cout<<ans+1<<"\n";
}