/* Problem URL: https://codeforces.com/contest/2134/problem/D */ #include #include #include using namespace std; using namespace __gnu_pbds; template > using ordered_set = tree; #define V vector #define rmin(a, b) a = min(a, b) #define rmax(a, b) a = max(a, b) #define rep(i, lim) for (int i = 0; i < (lim); i++) #define nrep(i, s, lim) for (int i = s; i < (lim); i++) #define repv(i, v) for (auto &i : (v)) #define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; } #define sortv(v) sort(v.begin(), v.end()) #define all(v) (v).begin(), (v).end() using vi = vector; using vvi = vector; using vvvi = vector; using vvvvi = vector; using ll = long long; using vl = vector; using vvl = vector; using vvvl = vector; using vvvvl = vector; template auto operator<<(ostream &os, const vector &vec)->ostream& { os << vec[0]; for (size_t i = 1; i < vec.size(); i++) { os << ' ' << vec[i]; } os << '\n'; return os; } template auto operator>>(istream &is, vector &vec)->istream& { for (auto &i : vec) { is >> i; } return is; } template auto operator<<(ostream &os, const vector> &vec)->ostream& { for (auto &i : vec) { os << i[0]; for (size_t j = 1; j < i.size(); j++) { os << ' ' << i[j]; } os << '\n'; } return os; } template auto operator>>(istream &is, vector> &vec)->istream& { for (auto &i : vec) { for (auto &j : i) { is >> j; } } return is; } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int t; cin >> t; while (t--) { int n; cin >> n; if (n == 1) { cout << "-1\n"; continue; } vvi graph(n); rep(i, n - 1) { int a, b; cin >> a >> b; a--, b--; graph[a].push_back(b); graph[b].push_back(a); } vi parent(n); auto bfs = [&](int i) { const int inf = INT32_MAX >> 1; vi dis(n, inf); queue q; dis[i] = 0; q.push(i); int ans = 0; while (!q.empty()) { i = q.front(); q.pop(); repv(j, graph[i]) { if (dis[j] > dis[i] + 1) { dis[j] = dis[i] + 1; q.push(j); ans = j; parent[j] = i; } } } return ans; }; int end1 = bfs(0); fill(all(parent), -1); int end2 = bfs(end1); int a, b, c; int p = end2; int now = parent[end2]; bool pos = false; while (parent[now] != -1 && !pos) { repv(j, graph[now]) { if (j == p || j == parent[now]) { continue; } a = p; b = now; c = j; pos = true; break; } p = now; now = parent[now]; } if (pos) { cout << a + 1 << ' ' << b + 1 << ' ' << c + 1 << '\n'; continue; } cout << "-1\n"; } }