#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline void _read(T& x) {
  cin >> x;
}
void R() {}
template <typename T, typename... U>
void R(T& head, U&... tail) {
  _read(head);
  R(tail...);
}
template <typename T>
inline void _write(const T& x) {
  cout << x << ' ';
}
void W() { cout << endl; }
template <typename T, typename... U>
void W(const T& head, const U&... tail) {
  _write(head);
  W(tail...);
}
template <typename T>
void debug(vector<T> V) {
  for (auto x : V) {
    cout << x << " ";
  }
  cout << endl;
}
void go();
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  go();
  return 0;
}
const int MAXN = 2e5 + 10;
vector<int> G[MAXN];
int dep[MAXN], sz[MAXN];
int depx;
int ask(char op, int u) {
  cout << op << " " << u << endl;
  int res;
  R(res);
  return res;
}
int pre(int u, int f) {
  sz[u] = 1;
  for (auto v : G[u]) {
    if (v == f) {
      continue;
    }
    dep[v] = dep[u] + 1;
    sz[u] += pre(v, u);
  }
  return sz[u];
}
vector<int> h;
void get(int u) {
  h.push_back(u);
  int big = -1;
  for (auto v : G[u]) {
    if (dep[v] > dep[u] && (big == -1 || sz[v] > sz[big])) {
      big = v;
    }
  }
  if (big != -1) {
    get(big);
  }
}
int dfs(int u) {
  h.clear();
  get(u);
  int depy = (depx + dep[h.back()] - ask('d', h.back())) / 2;
  int v = h[depy - dep[u]];
  if (depx == depy) {
    return v;
  }
  return dfs(ask('s', v));
}
void go() {
  int n;
  R(n);
  for (int i = 2; i <= n; i++) {
    int x, y;
    R(x, y);
    G[x].push_back(y);
    G[y].push_back(x);
  }
  depx = ask('d', 1);
  pre(1, -1);
  cout << "! " << dfs(1) << endl;
}
