#include "bits/stdc++.h"
#include <algorithm>
#include <array>
using namespace std;

using ll = long long;
using pii = pair<int, int>;

void solve() {
	int n;
	cin >> n;
	vector<vector<int>> edge(n, vector<int>());
	vector<pii> deg(n);
	for (int i = 0; i < n - 1; i++) deg[i] = {0, i};
	for (int i = 0; i < n - 1; i++) {
		int u, v;
		cin >> u >> v;
		--u, --v;
		edge[u].push_back(v), edge[v].push_back(u);
		deg[u].first++;
		deg[v].first++;
	}
	sort(rbegin(deg), rend(deg));
	if (deg[0].first == n - 1) {
		cout << -1 << "\n";
		return;
	}

	int total_leaf = 0;

	map<int, int> M;
	for (int i = 0; i < n; i++) {
		if (edge[i].size() == 1) {
			M[edge[i][0]]++;
			++total_leaf;
		}
	}

	int m = max_element(M.begin(), M.end())->second;

	int ans = (total_leaf + 1) / 2;
	ans = max(ans, m);
	cout << ans << "\n";
}

int main() {
	cin.tie(0)->sync_with_stdio(0);
	int t;
	cin >> t;
	while (t--) {
		solve();
	}
}