#include<iostream>
#include<algorithm>
#include<numeric>
using namespace std;
enum limits
{
    maxn =  500
};
int n, deg[maxn + 7], p[maxn + 7];
char s[14];
bool check(int);
int main()
{
    cin.tie(nullptr)->sync_with_stdio(false);
    cin >> n;
    for(int i=1, u, v; i<n; i++)
        cin >> u >> v, deg[u]++, deg[v]++;
    iota(p+1, p+n+1, 1);
    sort(p+1, p+n+1, [](int a, int b) { return deg[a] < deg[b]; } );
    int l = 1, r = n;
    while(r - l + 1 > 2 || (r == l + 1 && deg[p[r]] != 1))
    {
        int m = (l + r) >> 1;
        if(check(m))
            r = m;
        else
            l = m + 1;
    }
    if(r - l + 1 == 2)
    {
        cout << "? " << p[l] << ' ' << (l == 1 ? p[3] : p[l - 1]) << endl, cin >> s;
        l = r = (s[0] == 'Y' ? l : r);   
    }
    cout << "! " << p[l] << endl;
}
bool check(int x)
{
    cout << "? ";
    for(int i=1; i<=x; i++)
        cout << p[i] << ' ';
    cout << endl, cin >> s;
    return s[0] == 'Y';
}