#include <bits/stdc++.h>
using namespace std;
int pct(int x) { return __builtin_popcount(x); }
int pct(long long x) { return __builtin_popcountll(x); }
int bt(int x) { return 31 - __builtin_clz(x); }
int bt(long long x) { return 63 - __builtin_clzll(x); }
int cdiv(int a, int b) { return a / b + !(a < 0 || a % b == 0); }
long long cdiv(long long a, long long b) {
  return a / b + !(a < 0 || a % b == 0);
}
int nxt_C(int x) {
  int c = x & -x, r = x + c;
  return (((r ^ x) >> 2) / c) | r;
}
long long nxt_C(long long x) {
  long long c = x & -x, r = x + c;
  return (((r ^ x) >> 2) / c) | r;
}
vector<int> get_bits(int mask) {
  vector<int> bb;
  while (mask) {
    int b = bt(mask);
    bb.push_back(b);
    mask ^= (1 << b);
  }
  reverse(bb.begin(), bb.end());
  return bb;
}
int get_mask(vector<int> v) {
  int mask = 0;
  for (int x : v) {
    mask ^= (1 << x);
  }
  return mask;
}
template <typename T>
void uniq(vector<T> &v) {
  sort(v.begin(), v.end());
  v.resize(unique(v.begin(), v.end()) - v.begin());
}
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
long long rand(long long l, long long r) {
  uniform_int_distribution<long long> uid(l, r);
  return uid(rng);
}
void sc() {}
template <typename Head, typename... Tail>
void sc(Head &H, Tail &...T) {
  cin >> H;
  sc(T...);
}
const int mod = 1e9 + 7;
int pwr(int a, long long b) {
  int ans = 1;
  while (b) {
    if (b & 1) ans = (ans * 1LL * a) % mod;
    a = (a * 1LL * a) % mod;
    b >>= 1;
  }
  return ans;
}
const int N = 1005;
vector<int> s[N];
int in[N];
int query(vector<int> v) {
  cout << "? " << (int)v.size() << " ";
  for (int x : v) {
    cout << x << " ";
  }
  cout << endl;
  int y;
  sc(y);
  return y;
}
int go(int l, int r, int maxi) {
  if (l == r) return l;
  int m = (l + r) >> 1;
  vector<int> v;
  for (int i = l; i <= m; i++) {
    v.push_back(i);
  }
  int q = query(v);
  if (q == maxi) {
    return go(l, m, maxi);
  } else {
    return go(m + 1, r, maxi);
  }
}
void solve() {
  memset(in, 0, sizeof in);
  int n, k;
  sc(n, k);
  for (int i = 1; i <= k; i++) {
    s[i].clear();
    int c;
    sc(c);
    for (int j = 1; j <= c; j++) {
      int x;
      sc(x);
      s[i].push_back(x);
      in[x] = i;
    }
  }
  vector<int> v;
  for (int i = 1; i <= n; i++) {
    v.push_back(i);
  }
  int maxi = query(v);
  int idx = go(1, n, maxi);
  int kk = in[idx];
  v.clear();
  for (int i = 1; i <= n; i++) {
    if (in[i] != kk) v.push_back(i);
  }
  int z = query(v);
  cout << "! ";
  for (int i = 1; i <= k; i++) {
    if (i == kk) {
      cout << z << " ";
    } else {
      cout << maxi << " ";
    }
  }
  cout << endl;
  string s;
  sc(s);
  if (s == "Incorrect") {
    exit(0);
  }
}
int main() {
  ios ::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t = 1;
  cin >> t;
  for (int tt = 1; tt <= t; tt++) {
    solve();
  }
  return 0;
}
