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

#define fi first
#define se second
#define pii pair<int,int>
#define pll pair<long long,long long>
#define pb push_back
#define debug(x) cerr<<#x<<"="<<x<<endl
#define pq priority_queue
#define inf 1e18;
#define rep(i,a,b) for (ll i=a;i<(b);i++)
#define MP make_pair
#define SZ(x) (int(x.size()))
#define mod 1000000007
#define ALL(x) x.begin(),x.end()
#define endl "\n"
void inc(ll &a,ll b) {a=(a+b)%mod;}
void dec(ll &a,ll b) {a=(a-b+mod)%mod;}
int lowbit(ll x) {return x&(-x);}


const ll maxn = 555;
vector<ll>alist[maxn];
vector<ll>v;
ll deg[maxn];

bool cmp(ll a,ll b){
	return deg[a]<deg[b];
}

void query(vector<ll>v){
	cout<<"?"<<" ";
	for(auto x:v)cout<<x<<" ";
	cout<<endl;
}

bool check(ll mid){
	vector<ll>tmp;
	rep(i,0,mid+1)tmp.pb(v[i]);
	query(tmp);
	string in;cin>>in;
	if(in=="YES")return 1;
	else return 0;
}
int main(){
	//ios::sync_with_stdio(0);
	//cin.tie(0);
	//comment out for interactives 
	ll n;cin>>n;
	rep(i,0,n-1){
		ll a,b;cin>>a>>b;
		alist[a].pb(b);
		alist[b].pb(a);
		deg[a]++;
		deg[b]++;
	}
	rep(i,1,n+1)v.pb(i);
	sort(ALL(v),cmp);
	//at least 3 leaves
	ll lo=0,hi=n-1;
	while(lo<hi-1){
		ll mid=(lo+hi+1)/2;
		if(check(mid)){//lca is in the current prefix
			hi=mid;
		}else{//lca is not in current prefix
			lo=mid;
		}
	}
	
	if(lo==0 and hi==1){
		vector<ll>tmp;
		tmp.pb(v[0]);tmp.pb(v[2]);
		query(tmp);
		string in;cin>>in;
		if(in=="YES")cout<<'!'<<" "<<v[0]<<endl;
		else cout<<'!'<<" "<<v[1]<<endl;
	}else{
		cout<<"!"<<" "<<v[hi]<<endl;
	}
	return 0;
}