#include<bits/stdc++.h>
using namespace std;
#define N 2055
const int inf=1e9;
int t,n,m,a[N],ans,dep[N],d[N];
bool vis[N];
vector<int>s[N],now;
bool check(){
    // printf("\n-------------\n");
    // for(auto v:now){printf("%d ",v);}
    for(int i=2;i<=m;++i)d[i]=d[i>>1]+1;
    for(int i=0;i<(int)now.size();++i)if(d[now[i]]>n-i)return 0;
    return 1;
}
void dfs(){
    if(now.size()>n)return;
    for(int i=1;i<=m;++i)s[i].clear();
    for(int i=1;i<=m;++i){
        if(a[i]==-1||dep[i>>1]==-1)dep[i]=-1;
        else dep[i]=dep[i>>1]+a[i];
    }
    for(int i=(1<<n);i<=m;++i)s[i].push_back(dep[i]);
    int u=0;
    for(int i=(1<<n)-1;i;--i){
        for(auto v:s[i<<1])s[i].push_back(v);
        for(auto v:s[i<<1|1])s[i].push_back(v);
        for(auto v:s[i]){
            if(v==-1)continue;
            if(vis[v]){u=i;break;}
            vis[v]=1;
        }
        for(auto v:s[i])if(v!=-1)vis[v]=0;
        if(u)break;
    }
    if(!u){
        if(check())ans=min(ans,(int)now.size());
    }else{
        int x=a[u<<1],y=a[u<<1|1];
        a[u<<1]=-1;now.push_back(u<<1);dfs();now.pop_back();a[u<<1]=x;
        a[u<<1|1]=-1;now.push_back(u<<1|1);dfs();now.pop_back();a[u<<1|1]=y;
    }
}
void sol(){
    scanf("%d",&n);m=(1<<(n+1))-1;
    for(int i=2;i<=m;++i)scanf("%d",&a[i]);
    ans=inf;dfs();printf("%d\n",ans==inf?-1:ans);
}
int main(){
    scanf("%d",&t);
    while(t--)sol();
    return 0;
}