#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5;
vector<int> g[N];
vector<int> p(N, -1);
vector<int> d(N, -1);
vector<bool> blc(N);
int dx;
int q(char op, int u) {
  cout << op << ' ' << u << endl;
  int r;
  cin >> r;
  return r;
}
void pre(int u) {
  for (int v : g[u]) {
    if (!~d[v]) {
      d[v] = d[u] + 1;
      p[v] = u;
      pre(v);
    }
  }
}
vector<int> sz(N);
int _n;
void comp_size(int u, int pa) {
  sz[u] = 1;
  for (int v : g[u]) {
    if (!blc[v] && v != pa) {
      comp_size(v, u);
      sz[u] += sz[v];
    }
  }
}
int fcd(int u, int pa) {
  for (int v : g[u]) {
    if (!blc[v] && v != pa && sz[v] > _n / 2) return fcd(v, u);
  }
  return u;
}
int cd(int u) {
  comp_size(u, 0);
  _n = sz[u];
  return fcd(u, 0);
}
int qcd(int u) {
  int v = cd(u);
  int dis = q('d', v);
  if (!dis) return v;
  blc[v] = true;
  if (d[v] + dis == dx) return qcd(q('s', v));
  return qcd(p[v]);
}
void solve() {
  int n;
  cin >> n;
  for (int i = 1; i < n; i++) {
    int x, y;
    cin >> x >> y;
    g[x].emplace_back(y);
    g[y].emplace_back(x);
  }
  dx = q('d', 1);
  d[1] = 0;
  pre(1);
  int res = qcd(1);
  cout << "! " << res;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  solve();
  cout << endl;
}
