#include <bits/stdc++.h>
#define ll long long
#define lson(u) (u<<1)
#define rson(u) ((u<<1)|1)
#pragma GCC optimize(4)

using namespace std;
const int N=2100;
int n,sz,ans,d[N];
vector<int> g[N];

void mergge(vector<int> &a,vector<int> &b,vector<int> &S) {
    S.clear();
    int lena=a.size(),lenb=b.size();
    int i=0,j=0;
    while(i<lena&&j<lenb) {
        if(a[i]==b[j]) {
            S.clear();
            return ;
        }
        if(a[i]<b[j]) S.push_back(a[i++]);
        if(a[i]>b[j]) S.push_back(b[j++]);
    }
    while(i<lena) S.push_back(a[i++]);
    while(j<lenb) S.push_back(b[j++]);
    return ;
}

void dfs(int p,int d) {
    if(p==0) {ans=d;return ;}
    mergge(g[lson(p)],g[rson(p)],g[p]);
    if(g[p].empty()) {
        if(++d==ans||d+__lg(p)>n) return ;
        g[p]=g[lson(p)];
        dfs(p-1,d);
        if(d<ans) {
            g[p]=g[rson(p)];
            dfs(p-1,d);
        }
    } else dfs(p-1,d);
    return ;
}

void solve() {
    cin>>n;
    sz=(1<<n);
    for(int i=2;i<(sz<<1);i++) {
        cin>>d[i];
        d[i]+=d[i>>1];
        if(i>=sz) {
            g[i].clear();
            g[i].push_back(d[i]);
        }
    }
    ans=0x3f3f3f3f;
    dfs(sz,0);
    if(ans>n) cout<<"-1\n";
    else cout<<ans<<"\n";
    return ;
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);

    int tc;cin>>tc;
    while(tc--) solve();
    return 0;
}