#include <bits/stdc++.h>
using namespace std;
#define int long long
#define nl '\n'
#define io ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)

signed main() {
	io; int n; cin >> n;
	vector<vector<int>> adjlist(n);
	int a,b;
	for (int i = 0; i < n-1; i++) {
		cin >> a >> b;
		adjlist[a].push_back(b);
		adjlist[b].push_back(a);
	}
	string temp;
	for (int i = 1; i <= n; i++) {

		cout << "? " << n-1 << ' ';
		for (int j = 1; j <= n; j++) {
			if (i == j) continue;
			cout << j << ' ';
		}
		cout << nl;
		cout.flush();
		cin >> temp;
		if (temp == "NO") {
			cout << "! " << i <<  nl;
			break;
		}
	}
}