#include <bits/stdc++.h>
#define x first
#define y second
using namespace std;
using ll=long long;
using pii=pair<int,int>;
using vi=vector<int>;
using vl=vector<ll>;
#define pb push_back
#define all(a) begin(a),end(a)

const int N=300010,MOD=1e9+7;
const char en='\n';
const ll LLINF=1ll<<60;

int t,par[N];
vi nei[N];
bool bio[N];

void dfs(int ka=-1)
{
	int x,c;
	cin>>x>>c;
	if (ka!=-1) nei[ka].pb(x);
	if ((int)nei[x].size()==c)
	{
		bio[x]=1;
		for (int i=0;i<c;++i) if (!bio[nei[x][i]])
		{
			par[nei[x][i]]=x;
			cout<<"> "<<i+1<<endl;
			dfs();
			int xx,cc;
			cin>>xx>>cc;
			assert(xx==x);
		}
		if (par[x]!=-1)
		{
			for (int i=0;i<c;++i) if (nei[x][i]==par[x])
			{
				cout<<"> "<<i+1<<endl;
			}
		}
		return;
	}
	else
	{
		cout<<"> "<<nei[x].size()+1<<endl;
		dfs(x);
	}
}

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin>>t;
	while (t--)
	{
		for (int i=1;i<=2500;++i) nei[i].clear(),bio[i]=0,par[i]=-1;
		dfs();
		cout<<"!";
		for (int i=1;i<=2500;++i) for (auto x: nei[i]) if (x>i) cout<<' '<<i<<' '<<x;
		cout<<endl;
		string r;
		cin>>r;
		if (r=="Wrong") exit(0);
	}
}