#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
int n;
vector<set<int>> adj;
set<int> leafList;
int ask(int u, int v) {
  cout << "? " << u + 1 << " " << v + 1 << '\n';
  cout.flush();
  int w;
  cin >> w;
  assert(w != -1);
  return (w - 1);
}
void answer(int r) {
  cout << "! " << (r + 1) << '\n';
  cout.flush();
  exit(0);
}
void purge(int z, int last, int blockpoint) {
  if (leafList.find(z) != leafList.end()) leafList.erase(z);
  for (int t : adj[z]) {
    if (t == last) continue;
    if (t == blockpoint)
      adj[t].erase(z);
    else if (adj[t].size() != 0)
      purge(t, z, blockpoint);
  }
  adj[z].clear();
}
void Input() {
  cin >> n;
  adj.resize(n);
  for (int i = 1; i < n; i++) {
    int x, y;
    cin >> x >> y;
    x--;
    y--;
    adj[x].insert(y);
    adj[y].insert(x);
  }
}
void Solve() {
  for (int i = 0; i < n; i++) {
    if (adj[i].size() == 1) leafList.insert(i);
  }
  while (leafList.size() > 1) {
    int u = *leafList.begin();
    leafList.erase(u);
    int v = *leafList.begin();
    leafList.erase(v);
    int w = ask(u, v);
    if (w == u || w == v) answer(w);
    purge(u, -1, w);
    purge(v, -1, w);
    if (adj[w].size() <= 1) leafList.insert(w);
  }
  answer(*leafList.begin());
}
int main(int argc, char* argv[]) {
  ios_base::sync_with_stdio(false);
  Input();
  Solve();
  return 0;
}
