#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int ll
#define rep(i,a,b) for(int i = a; i < (b); i++)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define PB push_back
#define FS first
#define SD second
template<class A, class B> void cmx(A& x, B y) {x=max<A>(x, y);}
template<class A, class B> void cmn(A& x, B y) {x=min<A>(x, y);}
typedef pair<int, int> pii;
typedef vector<int> vi;

int tim = 0;
int lastvis[1000002];
int parent[1000002];
int from[1000002];
int fromid[1000002];
int odw[1000002];
int t[1000002];
vector<pii> answer;

void touch(int x) {
    if (t[x] != tim) {
        t[x] = tim;
        from[x] = -1;
        lastvis[x] = 0;
        odw[x] = 0;
    }
}

void fun() {
    answer.clear();
    tim++;
    int curv, deg;
    cin >> curv >> deg;
    touch(curv);
    parent[curv] = -1;
    odw[curv] = 1;
    while (true) {
        touch(curv);
        if (lastvis[curv] == deg) {
            if (parent[curv] == -1) {
                cout << "! ";
                sort(all(answer));
                for (int i = 0; i < sz(answer); i++) {
                    if (i == 0 || answer[i] != answer[i-1])
                        cout << answer[i].FS << " " << answer[i].SD << " ";
                }
                cout << endl;
                string slo;
                cin >> slo;
                return;
            } else {
                cout << "> " << parent[curv] << endl;
            }
            cin >> curv >> deg;
        } else {
            cout << "> " << ++lastvis[curv] << endl;
            int newv;
            cin >> newv >> deg;
            answer.PB(minmax(newv, curv));
            touch(newv);
            if (odw[newv] == 0) {
                from[newv] = curv;
                fromid[newv] = lastvis[curv];
                odw[newv] = 1;
                curv = newv;
            } else if (newv == from[curv]) {
                parent[curv] = lastvis[curv];
                cout << "> " << fromid[curv] << endl;
                cin >> curv >> deg;
            } else {
                curv = newv;
            }
        }
    }
}

signed main() {
//    cin.tie(0)->sync_with_stdio(0); cin.exceptions(cin.failbit);
    int tt;
    cin >> tt;
    while (tt--) fun();
}