#include <bits/stdc++.h>
using namespace std;
vector<vector<int> > g;
vector<int> sz;
vector<int> dep, p;
int d;
void dfs1(int cur, int par, int depth, int tar) {
  sz[cur] = 0;
  dep[cur] = depth;
  p[cur] = par;
  if (depth > tar) return;
  if (depth == tar) {
    sz[cur] = 1;
    return;
  }
  for (int u : g[cur]) {
    if (u == par) continue;
    dfs1(u, cur, depth + 1, tar);
    sz[cur] += sz[u];
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  int qc = 1;
  g.resize(n);
  for (int i = 0; i < n - 1; i++) {
    int u, v;
    cin >> u >> v;
    u--, v--;
    g[u].push_back(v);
    g[v].push_back(u);
  }
  sz.resize(n);
  dep.resize(n);
  p.resize(n);
  cout << "d " << 1 << endl;
  cin >> d;
  if (d == 0) {
    cout << "! 1" << endl;
    return 0;
  }
  dfs1(0, -1, 0, d);
  int cur = 0;
  while (dep[cur] < d) {
    int v = cur;
    while (dep[v] < d) {
      int best = -1;
      assert(sz[v] > 0);
      for (int u : g[v]) {
        if (u == p[v]) continue;
        if (best == -1 || sz[u] > sz[best]) best = u;
      }
      v = best;
    }
    qc++;
    assert(qc <= 36);
    int dis;
    cout << "d " << v + 1 << endl;
    cin >> dis;
    if (dis == 0) {
      cur = v;
      break;
    }
    assert(dis != -1);
    int lca = v;
    for (int i = 0; i < dis / 2; i++) {
      if (lca == -1) return 4;
      lca = p[lca];
    }
    qc++;
    assert(qc <= 36);
    cout << "s " << lca + 1 << endl;
    cin >> cur;
    assert(cur != -1);
    cur--;
  }
  cout << "! " << cur + 1 << endl;
}
