#include<bits/stdc++.h>
#define ls i<<1
#define rs i<<1|1
#define fi first
#define se second
#define min amin
#define max amax
#define eb emplace_back
using namespace std;
using ll=long long;
using LL=__int128;
using pii=pair<int,int>;
const int N=1<<20;
const int inf=0x3f3f3f3f;
const int p=998244353;
template<typename T=int>T read(){T x;cin>>x;return x;}
template<typename U,typename V>U min(const U &x,const V &y){return x<y?x:y;}
template<typename U,typename V>U max(const U &x,const V &y){return y<x?x:y;}
template<typename U,typename ...V>U min(const U &x,const V &...y){return min(x,min(y...));}
template<typename U,typename ...V>U max(const U &x,const V &...y){return max(x,max(y...));}
template<typename U,typename V>bool cmin(U &x,const V &y){return y<x?x=y,true:false;}
template<typename U,typename V>bool cmax(U &x,const V &y){return x<y?x=y,true:false;}
template<typename U,typename ...V>bool cmin(U &x,const V &...y){return cmin(x,min(y...));}
template<typename U,typename ...V>bool cmax(U &x,const V &...y){return cmax(x,max(y...));}
template<typename U,typename V>U qpow(U x,V n){U y(1);for(;n;n>>=1,x*=x)if(n&1)y*=x;return y;}
ll sqrt_floor(const ll &x){ll l=0,r=inf;while(l+1^r){ll mid=l+r>>1;(x<mid*mid?r:l)=mid;}return l;}
ll sqrt_ceil(const ll &x){ll l=-1,r=inf;while(l+1^r){ll mid=l+r>>1;(mid*mid<x?l:r)=mid;}return r;}
istream &operator>>(istream &is,LL &x){string a;is>>a;bool k=a[0]=='-';if(k)a=a.substr(1);x=0;for(char &t:a)x=x*10+t-48;if(k)x=-x;return is;}
ostream &operator<<(ostream &os,LL x){if(x<0)os<<'-',x=-x;string a;do a+=x%10|48;while(x/=10);reverse(a.begin(),a.end());return os<<a;}
mt19937 rng(time(0));
struct mint{
    int x;
    mint():x(){}
    mint(const int &x):x(x<0?x+p:x){}
    mint inv()const{return qpow(*this,p-2);}
    mint operator-()const{return mint(x?p-x:x);}
    mint &operator+=(const mint &t){return (x+=t.x)<p?0:x-=p,*this;}
    mint &operator-=(const mint &t){return (x-=t.x)<0?x+=p:0,*this;}
    mint &operator*=(const mint &t){return x=ll(x)*t.x%p,*this;}
    mint &operator/=(const mint &t){return *this*=t.inv();}
    mint operator+(const mint &t)const{return mint(*this)+=t;}
    mint operator-(const mint &t)const{return mint(*this)-=t;}
    mint operator*(const mint &t)const{return mint(*this)*=t;}
    mint operator/(const mint &t)const{return mint(*this)/=t;}
    operator int()const{return x;}
    bool operator==(const mint &t)const{return x==t.x;}
    friend mint operator+(const mint &x,const int &y){return mint(x)+=y;}
    friend mint operator-(const mint &x,const int &y){return mint(x)-=y;}
    friend mint operator*(const mint &x,const int &y){return mint(x)*=y;}
    friend mint operator/(const mint &x,const int &y){return mint(x)/=y;}
    friend mint operator+(const int &x,const mint &y){return mint(x)+=y;}
    friend mint operator-(const int &x,const mint &y){return mint(x)-=y;}
    friend mint operator*(const int &x,const mint &y){return mint(x)*=y;}
    friend mint operator/(const int &x,const mint &y){return mint(x)/=y;}
    friend istream &operator>>(istream &is,mint &t){return is>>t.x;}
    friend ostream &operator<<(ostream &os,const mint &t){return os<<t.x;}
};

int a[N],n,ans;
vector<int>q[N];
void mg(vector<int>&a,vector<int>&b,vector<int>&c){
    auto i=a.begin(),j=b.begin();
    while(i!=a.end()||j!=b.end()){
        if(*i==*j)return c.clear();
        if(*i<*j){
            c.eb(*i);
            ++i;
        }
        else{
            c.eb(*j);
            ++j;
        }
    }
    for(;i!=a.end();++i){
        c.eb(*i);
    }
    for(;j!=b.end();++j){
        c.eb(*j);
    }
}
void dfs(int i,int s){
    if(!--i)return void(ans=s);
    mg(q[ls],q[rs],q[i]);
    if(q[i].empty()){
        ++s;
        if(s==ans||s+__lg(i)>n)return;
        q[i]=q[ls];
        dfs(i,s);
        if(s<ans){
            q[i]=q[rs];
            dfs(i,s);
        }
    }
    else{
        dfs(i,s);
    }
}
void solve(){
    cin>>n;
    int s=1<<n;
    for(int i=2;i<s<<1;++i){
        cin>>a[i];
        a[i]+=a[i>>1];
        if(i<s)q[i].clear();
        else q[i].assign(1,a[i]);
    }
    ans=inf;
    dfs(s,0);
    cout<<(ans^inf?ans:-1)<<'\n';
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int T;
    cin>>T;
    while(T--){
        solve();
    }
    return 0;
}