#include<bits/stdc++.h>
using namespace std;

int N;
vector<int>G[2<<17];
int seen[2<<17],sz[2<<17];

int cent(int root){
	auto dfs=[&](auto&&dfs,int now,int pre)->int{
		sz[now]=1;
		for(int nxt:G[now]){
			if(nxt==pre||seen[nxt])continue;
			sz[now]+=dfs(dfs,nxt,now);
		}
		return sz[now];
	};
	int total=dfs(dfs,root,-1);
	int cent=root;
	auto dfs2=[&](auto&&dfs2,int now,int pre)->void{
		bool ok=(total-sz[now])*2<=total;
		for(int nxt:G[now]){
			if(nxt==pre||seen[nxt])continue;
			dfs2(dfs2,nxt,now);
			if(sz[nxt]*2>total)ok=false;
		}
		if(ok)cent=now;
	};
	dfs2(dfs2,root,-1);
	return cent;
}

int ask(int u,int v){
	cout<<"? "<<++u<<' '<<++v<<endl;
	int ret;cin>>ret;
	return ret;
}

int main(){
	int T;cin>>T;
	
	while(T--){
		int N;cin>>N;
		for(int i=0;i<N;i++){
			G[i].clear();
			seen[i]=false;
			sz[i]=0;
		}
		for(int i=0;i<N;i++){
			int u,v;cin>>u>>v;
			u--;v--;
			if(u>=0){
				G[i].push_back(u);
				G[u].push_back(i);
			}
			if(v>=0){
				G[i].push_back(v);
				G[v].push_back(i);
			}
		}

		int ans=-1;
		auto solve=[&](auto&&solve,int now)->void{
			int ce=cent(now);
			seen[ce]=true;

			vector<int>ch;
			for(int nxt:G[ce]){
				if(!seen[nxt])ch.push_back(nxt);
			}

			int deg=ch.size();
			if(deg==0){
				ans=ce;
			}else if(deg==1){
				int res=ask(ce,ch.front());

				if(res==0){
					seen[ch.front()]=true;
					solve(solve,ce);
				}else if(res==2){
					solve(solve,ch.front());
				}
			}else if(deg==2){
				int le=ch[0],ri=ch[1];
				int res=ask(le,ri);

				if(res==0)solve(solve,le);
				else if(res==1)ans=ce;
				else solve(solve,ri);
			}else if(deg==3){
				int res=ask(ch[0],ch[1]);

				if(res==1){
					seen[ce]=false;
					seen[ch[0]]=true;
					seen[ch[1]]=true;
					solve(solve,ce);
				}
				else if(res==0) solve(solve,ch[0]);
				else solve(solve,ch[1]);
			}
		};

		solve(solve,0);
		cout<<"! "<<++ans<<endl;
	}
}