#include<iostream>
using namespace std;
#include<vector>
#include<queue>
#include<algorithm>
#include<numeric>
#include<cmath>
#include<unordered_map>

using i64 = long long;

void solve() {
	int n = 0;
	cin >> n;

	vector<i64> a((1 << (n + 1)));
	for (int i = 2; i < (1 << (n + 1)); ++i) {
		cin >> a[i];
		a[i] += a[i >> 1];
	}
	
	vector<i64> b(1 << n), p(1 << n);
	for (int i = 0; i < (1 << n); ++i) {
		b[i] = a[(1 << n) + i];
		p[i] = b[i];
	}

	sort(p.begin(), p.end());
	p.erase(unique(p.begin(), p.end()), p.end());

	unordered_map<i64, int> mp;
	for (int i = 0; i < p.size(); ++i) mp[p[i]] = i + 1;
	for (int i = 0; i < (1 << n); ++i) b[i] = mp[b[i]];

	int tot = p.size();
	int sum = 0;

	int N = 1e6;
	vector<int> num(N);

	for (int i = 1; i <= n; ++i) {
		int d = 1 << i;
		for (int j = 0; j < (1 << n); j += d) {
			for (int k = j; k < j + (d >> 1); ++k) {
				num[b[k]]++;
			}
			bool ok = false;
			for (int k = j + (d >> 1); k < j + d; ++k) {
				if (num[b[k]] > 0) {
					ok = true;
					break;
				}
			}
			if (ok) ++sum;
			for (int k = j; k < j + (d >> 1); ++k) {
				num[b[k]]--;
				if (ok) b[k] = ++tot;
			}
		}
		if (sum > i) {
			cout << "-1\n";
			return;
		}
	}

	cout << sum << "\n";
	return;
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

	int t = 1;
	cin >> t;
	while (t--) solve();

	return 0;
}