#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <vector>

using namespace std;

// BEGIN NO SAD
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define trav(a, x) for(auto& a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
typedef vector<int> vi;
#define f first
#define s second
#define derr if(1) cerr

void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
 
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#define debug(x...) cerr << "\e[91m"<<__func__<<":"<<__LINE__<<" [" << #x << "] = ["; _print(x); cerr << "\e[39m" << flush;
// END NO SAD

template<class Fun>
class y_combinator_result {
  Fun fun_;
public:
  template<class T>
  explicit y_combinator_result(T &&fun): fun_(std::forward<T>(fun)) {}

  template<class ...Args>
  decltype(auto) operator()(Args &&...args) {
    return fun_(std::ref(*this), std::forward<Args>(args)...);
  }
};

template<class Fun>
decltype(auto) y_combinator(Fun &&fun) {
  return y_combinator_result<std::decay_t<Fun>>(std::forward<Fun>(fun));
}

template<class T>
bool updmin(T& a, T b) {
  if(b < a) {
    a = b;
    return true;
  }
  return false;
}
template<class T>
bool updmax(T& a, T b) {
  if(b > a) {
    a = b;
    return true;
  }
  return false;
}
typedef int64_t ll;

void rsolve() {
  int currloc, currdeg;
  cin >> currloc >> currdeg;
  vector<map<int, int>> edges; // edges[i] stores vertex -> edge index
  vector<set<int>> unexplored;
  vector<int> st;
  st.pb(currloc);
  while(true) {
    assert(st.back() == currloc);
    if(currloc >= sz(edges)) {
      edges.resize(currloc+1);
      unexplored.resize(currloc+1);
    }
    if(sz(edges[currloc]) == 0 && sz(unexplored[currloc]) == 0) {
      for(int a = 1; a <= currdeg; a++) unexplored[currloc].insert(a);
    }
    if(sz(unexplored[currloc])) {
      // explore something at random
      int edgeidx = *unexplored[currloc].begin();
      unexplored[currloc].erase(edgeidx);
      cout << "> " << (edgeidx) << endl << flush;
      int nloc, ndeg;
      cin >> nloc >> ndeg;
      edges[currloc][nloc] = edgeidx;
      st.pb(nloc);
      currloc = nloc;
      currdeg = ndeg;
    }
    else {
      if(sz(st) == 1) break;
      assert(currloc == st.back()); st.pop_back();
      int edgetoprint = -1;
      int target = -1;
      int floor = 0;
      for(int j = 0; j < sz(st); j++) {
        if(sz(unexplored[st[j]])) floor = j;
      }
      for(int k = floor; k < sz(st); k++) {
        int cand = st[k];
        if(edges[currloc].count(cand)) {
          target = cand;
          edgetoprint = edges[currloc][cand];
          st.resize(k+1);
          break;
        }
      }
      assert(target >= 0);
      cout << "> " << edgetoprint << endl << flush;
      int nloc, ndeg;
      cin >> nloc >> ndeg;
      currloc = nloc;
      currdeg = ndeg;
    }
  }
  cout << "!";
  for(int i = 1; i < sz(edges); i++) {
    for(auto [a, b]: edges[i]) {
      if(a > i) cout << " " << i << " " << a;
    }
  }
  cout << endl << flush;
  string ans;
  cin >> ans;
  assert(ans == "Correct");
}
void solve() {
  int t;
  cin >> t;
  while(t--) rsolve();
}

// what would chika do
// are there edge cases (N=1?)
// are array sizes proper (scaled by proper constant, for example 2* for koosaga tree)
// integer overflow?
// DS reset properly between test cases
// are you doing geometry in floating points
// are you not using modint when you should

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  solve();
}