using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    static int[] NMi => ReadLine().Split().Select(c => int.Parse(c) - 1).ToArray();
    static int[][] NMap(int n) => Enumerable.Repeat(0, n).Select(_ => NMi).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var map = NMap(n - 1);

        var tree = new List<int>[n];
        for (var i = 0; i < tree.Length; ++i) tree[i] = new List<int>();
        foreach (var edge in map)
        {
            tree[edge[0]].Add(edge[1]);
            tree[edge[1]].Add(edge[0]);
        }
        var color = new int[n];
        color[0] = 1;
        DFS(0, tree, color);

        var plus = new List<int>();
        var minus = new List<int>();
        for (var i = 0; i < n; ++i)
        {
            if (color[i] > 0) plus.Add(i);
            else minus.Add(i);
        }
        var q = new List<int>(n - 1);
        for (var i = 0; i < n - 1; ++i)
        {
            if (color[map[i][0]] == 1) q.Add(map[i][0]);
            else q.Add(map[i][1]);
        }
        List<int> target;
        if (Query(q)) target = plus;
        else target = minus;
        var ans = new bool[n];
        foreach (var ti in target) ans[ti] = true;
        var index = Enumerable.Repeat(-1, n).ToArray();
        for (var i = 0; i < target.Count; ++i) index[target[i]] = i;
        for (var b = 1; b < target.Count; b *= 2)
        {
            var nq = new List<int>(n - 1);
            for (var i = 0; i < n - 1; ++i)
            {
                if (index[map[i][0]] >= 0)
                {
                    if ((index[map[i][0]] & b) == 0) nq.Add(map[i][0]);
                    else nq.Add(map[i][1]);
                }
                else
                {
                    if ((index[map[i][1]] & b) == 0) nq.Add(map[i][1]);
                    else nq.Add(map[i][0]);
                }
            }
            if (Query(nq))
            {
                for (var i = 0; i < target.Count; ++i) if ((i & b) != 0) ans[target[i]] = false;
            }
            else
            {
                for (var i = 0; i < target.Count; ++i) if ((i & b) == 0) ans[target[i]] = false;
            }
        }
        for (var i = 0; i < n; ++i) if (ans[i]) WriteLine($"! {i + 1}");
    }
    static void DFS(int cur, List<int>[] tree, int[] color)
    {
        foreach (var next in tree[cur])
        {
            if (color[next] != 0) continue;
            color[next] = -color[cur];
            DFS(next, tree, color);
        }
    }
    static bool Query(List<int> q)
    {
        WriteLine($"? {string.Join(" ", q.Select(qi => qi + 1))}");
        var s = ReadLine();
        if (s == "Yes") return true;
        else if (s == "No") return false;
        throw new Exception();
    }
}