#include <bits/stdc++.h>
#define _rep(i, x, y) for(int i = x; i <= y; ++i)
#define _req(i, x, y) for(int i = x; i >= y; --i)
#define _rev(i, u) for(int i = head[u]; i; i = e[i].nxt)
#define pb push_back
#define fi first
#define se second
#define mst(f, i) memset(f, i, sizeof f)
using namespace std;
#ifdef ONLINE_JUDGE
#define debug(...) 0
#else
#define debug(...) fprintf(stderr, __VA_ARGS__), fflush(stderr)
#endif
typedef long long ll;
typedef pair<int, int> PII;
namespace fastio{
    #ifdef ONLINE_JUDGE
    char ibuf[1 << 20],*p1 = ibuf, *p2 = ibuf;
    #define get() p1 == p2 && (p2 = (p1 = ibuf) + fread(ibuf, 1, 1 << 20, stdin), p1 == p2) ? EOF : *p1++
    #else
    #define get() getchar()
    #endif
    template<typename T> inline void read(T &t){
        T x = 0, f = 1;
        char c = getchar();
        while(!isdigit(c)){
            if(c == '-') f = -f;
            c = getchar();
        }
        while(isdigit(c)) x = x * 10 + c - '0', c = getchar();
        t = x * f;
    }
    template<typename T, typename ... Args> inline void read(T &t, Args&... args){
        read(t);
        read(args...);
    }
    template<typename T> void write(T t){
        if(t < 0) putchar('-'), t = -t;
        if(t >= 10) write(t / 10);
        putchar(t % 10 + '0');
    }
    template<typename T, typename ... Args> void write(T t, Args... args){
        write(t), putchar(' '), write(args...);
    }
    template<typename T> void writeln(T t){
        write(t);
        puts("");
    }
    template<typename T> void writes(T t){
        write(t), putchar(' ');
    }
    #undef get
};
using namespace fastio;
#define multitest() int T; read(T); _rep(tCase, 1, T)
namespace Calculation{
    const ll mod = 998244353;
    ll ksm(ll p, ll h){ll base = p % mod, res = 1; while(h){if(h & 1ll) res = res * base % mod; base = base * base % mod, h >>= 1ll;} return res;}
    void dec(ll &x, ll y){x = ((x - y) % mod + mod) % mod;}
    void add(ll &x, ll y){x = (x + y) % mod;}
    void mul(ll &x, ll y){x = x * y % mod;}
    ll sub(ll x, ll y){return ((x - y) % mod + mod) % mod;}
    ll pls(ll x, ll y){return ((x + y) % mod + mod) % mod;}
    ll mult(ll x, ll y){return x * y % mod;}
}
using namespace Calculation;
const int N = (1 << 11) + 5;
ll n, m, w[15], a[N], dis[N], dep[N];
bool vis[N];
int rt;
vector<ll> f[N];
void clr(){
    _rep(i, 1, n) a[i] = dis[i] = dep[i] = vis[i] = 0, f[i].clear();
    rt = n = m = 0;
}
vector<ll> merge(vector<ll> a, vector<ll> b){
    auto lit = a.begin(), rit = b.begin();
    vector<ll> c;
    while(lit != a.end() || rit != b.end()){
        if(rit == b.end() || (lit != a.end() && (*lit) <= (*rit))) c.pb(*lit), lit++;
        else c.pb(*rit), rit++;
    }
    return c;
}
void dfs(int u){
    if(dep[u] == m) return f[u] = {dis[u]}, void();
    dis[u << 1] = dis[u] + a[u << 1], dis[u << 1 | 1] = dis[u] + a[u << 1 | 1];
    if(!vis[u << 1]) dfs(u << 1);
    if(!vis[u << 1 | 1]) dfs(u << 1 | 1);
    f[u] = merge(f[u << 1], f[u << 1 | 1]);
    int len = f[u].size();
    bool flag = 0;
    _rep(i, 0, len - 2) if(f[u][i] == f[u][i + 1]){flag = 1; break;}
    if(flag && (!rt || dep[u] > dep[rt])) rt = u;
}
int ans;
void solve(int u){
    if(u > m + 1) return;
    rt = 0; _rep(i, 1, n) f[i].clear(), dis[i] = 0;
    dfs(1);
    if(!rt){
        ans = min(ans, u - 1);
        return;
    }
    int t = rt;
    if(!w[dep[t]]) return;
    w[dep[t]]--;
    vis[t << 1] = 1;
    solve(u + 1);
    vis[t << 1] = 0, vis[t << 1 | 1] = 1;
    solve(u + 1);
    vis[t << 1 | 1] = 0;
    w[dep[t]]++;
}
int main(){
    multitest(){
        read(m), n = (1 << m + 1) - 1;
        _rep(i, 2, n) read(a[i]), dep[i] = dep[i >> 1] + 1;
        _rep(i, 0, m) w[i] = m - i;
        ans = 0721;
        solve(1);
        if(ans == 0721) puts("-1");
        else writeln(ans);
        clr();
    }
    return 0;
}