#include <bits/stdc++.h>

using namespace std;

using i64 = long long;

void solve(){
    int n;
    cin >> n;
    vector<vector<int>>adj(n + 1);
    for (int i = 0;i < n - 1;i ++){
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    for (int i = 1;i <= n;i ++){
        if (adj[i].size() == n - 1){
            cout << -1 << '\n';
            return;
        }
    }

    vector<int>dep(n + 1);
    int cnt = 0;
    auto dfs = [&](auto self, int u, int p) -> void{
        dep[u] = dep[p] + 1;
        for (auto v : adj[u]){
            if (v == p) continue;
            self(self, v, u);        
        }
        if (adj[u].size() == 1 && u != 1){
            cnt ++;
        }
    };dfs(dfs, 1, 0);

    cout << cnt << '\n';
}

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

    int T = 1;
    cin >> T;
    while (T --){
        solve();
    }
    return 0;
}