#include <bits/stdc++.h>
#define inf 1000000007
#define mod 1000000007
// #define int long long
// #pragma GCC optimize("Ofast","inline","-ffast-math")
// #pragma GCC target("avx,sse2,sse3,sse4,mmx")
using namespace std;
template <typename T> void read(T &x){
	x=0;char ch=getchar();int fh=1;
	while (ch<'0'||ch>'9'){if (ch=='-')fh=-1;ch=getchar();}
	while (ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();
	x*=fh;
}
template <typename T> void write(T x) {
	if (x<0) x=-x,putchar('-');
	if (x>9) write(x/10);
	putchar(x%10+'0');
}
template <typename T> void writeln(T x) {
	write(x);
	puts("");
}
int n,cnt;
int h[100005],e[200005],ne[200005],idx;
bool cut[200005];
vector<int> vis;
void add(int a,int b)
{
	e[idx]=b,cut[idx]=0,ne[idx]=h[a],h[a]=idx++;
}
int rt,mn,all;
int siz[100005];
void dfs(int x,int fa)
{
	vis.push_back(x);
	siz[x]=1;
	for(int i=h[x];~i;i=ne[i])
	{
		int j=e[i];
		if(i==fa||cut[i]) continue;
		dfs(j,i^1);
		siz[x]+=siz[j];
		if(mn>max(siz[j],all-siz[j]))
			mn=max(siz[j],all-siz[j]),rt=i;
	}
}
int ask(int u,int v)
{
	++cnt;
	if(u==3&&v==5)
	{
		writeln(n);
		for(int i=0;i<idx;i+=2)
			write(e[i]),putchar(' '),write(e[i^1]),putchar(',');
		exit(0);
	}
	if(cnt>(int)log2(n)) assert(0);
	printf("? %d %d\n",u,v);
	fflush(stdout);
	int ret;
	read(ret);
	return ret;
}
int solve()
{
	if(all==1) return e[rt];
	if(all==2)
	{
		if(ask(e[rt],e[rt^1])) rt^=1;
		return e[rt];
	}
	if(all==3)
	{
		sort(vis.begin(),vis.end(),[](int a,int b){return siz[a]<siz[b];});
		if(siz[vis[1]]==2)
		{
			int r=ask(vis[0],vis[2]);
			if(r==0) return vis[0];
			if(r==1) return vis[1];
			if(r==2) return vis[2];
		}
		else
		{
			int r=ask(vis[0],vis[1]);
			if(r==0) return vis[0];
			if(r==1) return vis[2];
			if(r==2) return vis[1];
		}
	}
	if(ask(e[rt],e[rt^1]))
		all=all-siz[e[rt]],mn=all,rt^=1;
	else
		all=siz[e[rt]],mn=all;
	cut[rt]=cut[rt^1]=1;vis.clear();
	dfs(e[rt],-1);
	return solve();
}
signed main()
{
	// freopen(".in","r",stdin);
	// freopen(".out","w",stdout);
	int tc;read(tc);
	while(tc--)
	{
		cnt=0;
		read(n);idx=0;
		for(int i=1;i<=n;++i)
			h[i]=-1;
		for(int i=1;i<=n;++i)
		{
			int x,y;
			read(x);read(y);
			if(x) add(x,i),add(i,x);
			if(y) add(i,y),add(y,i);
		}
		rt=0;mn=all=n;vis.clear();
		dfs(e[rt],-1);
		printf("! %d\n",solve());
		fflush(stdout);
	}
	return 0;
}