#include <bits/stdc++.h>
using namespace std;
const int MAXN = 200005;
int n;
vector<int> par(MAXN, -1);
vector<int> pos(MAXN, -1);
vector<vector<int> > g;
vector<vector<int> > h;
vector<vector<int> > tb;
int d = 0;
void dfs(int u, int p, int tall) {
  if (h.size() <= tall) h.push_back(vector<int>());
  h[tall].push_back(u);
  par[u] = p;
  pos[u] = h[tall].size() - 1;
  for (int v : g[u]) {
    if (v != p) {
      dfs(v, u, tall + 1);
    }
  }
}
void initTable() {
  tb.assign(n, vector<int>(20, -1));
  for (int i = 0; i < n; ++i) tb[i][0] = par[i];
  for (int i = 1; i < 20; ++i) {
    for (int j = 0; j < n; ++j) {
      if (tb[j][i - 1] != -1) tb[j][i] = tb[tb[j][i - 1]][i - 1];
    }
  }
}
int lift(int u, int k) {
  for (int i = 19; i >= 0; --i) {
    if (k >= (1 << i)) {
      k -= (1 << i);
      u = tb[u][i];
    }
  }
  return u;
}
signed main() {
  cin >> n;
  g.assign(n, vector<int>());
  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);
  }
  dfs(0, -1, 0);
  initTable();
  cout << "d 1" << endl;
  cin >> d;
  int l = 0, r = h[d].size() - 1;
  while (l <= r) {
    int mid = (l + r) >> 1;
    cout << "d " << h[d][mid] + 1 << endl;
    int dist;
    cin >> dist;
    if (dist == 0) {
      cout << "! " << h[d][mid] + 1 << endl;
      return 0;
    }
    dist /= 2;
    int u = lift(h[d][mid], dist);
    int v = lift(h[d][mid], dist - 1);
    cout << "s " << u + 1 << endl;
    int uu;
    cin >> uu;
    --uu;
    if (pos[v] > pos[uu]) {
      r = mid - 1;
    } else
      l = mid + 1;
  }
}
