#include <bits/stdc++.h>
using namespace std;
const int X = 69;
const int MAXN = 2e5 + 5;
int n;
vector<int> graph[MAXN];
int parent[MAXN];
int depth[MAXN];
int baseDist;
int treeSize[MAXN];
bool wasCentroid[MAXN];
int DFSAnswer1(int x, int last, int dist) {
  if (x == X) return dist;
  for (int y : graph[x]) {
    if (y != last) {
      int val = DFSAnswer1(y, x, dist + 1);
      if (val != -1) return val;
    }
  }
  return -1;
}
int DFSAnswer2(int x, int last, int dist) {
  if (x == X) return x;
  for (int y : graph[x]) {
    if (y != last) {
      int val = DFSAnswer2(y, x, dist + 1);
      if (val != -1) return y;
    }
  }
  return -1;
}
int answerQuery1(int u) { return DFSAnswer1(u, -1, 0); }
int answerQuery2(int u) { return DFSAnswer2(u, parent[u], 0); }
int query1(int u) {
  cout << "d " << u << '\n';
  cout.flush();
  int ans;
  cin >> ans;
  return ans;
}
int query2(int u) {
  cout << "s " << u << '\n';
  cout.flush();
  int ans;
  cin >> ans;
  return ans;
}
void DFSInit1(int x, int last, int level) {
  depth[x] = level;
  parent[x] = last;
  for (int y : graph[x]) {
    if (y != last) {
      DFSInit1(y, x, level + 1);
    }
  }
}
void DFSInit2(int x, int last) {
  treeSize[x] = 1;
  for (int y : graph[x]) {
    if (y == last) continue;
    if (wasCentroid[y] == true) continue;
    DFSInit2(y, x);
    treeSize[x] += treeSize[y];
  }
}
int findCentroid(int x) {
  int root = x;
  bool change = false;
  int last = -1;
  int centroid = x;
  DFSInit2(x, -1);
  do {
    change = false;
    for (int y : graph[centroid]) {
      if (y == last) continue;
      if (wasCentroid[y] == true) continue;
      if (treeSize[y] > treeSize[root] / 2) {
        last = centroid;
        centroid = y;
        change = true;
        break;
      }
    }
  } while (change == true);
  return centroid;
}
bool isAncestor(int x) {
  int dist = query1(x);
  if (dist == 0) {
    cout << "! " << x << '\n';
    cout.flush();
    exit(0);
  }
  if (baseDist == depth[x] + dist) return true;
  return false;
}
int solve(int x) {
  int centroid = findCentroid(x);
  wasCentroid[centroid] = true;
  if (treeSize[x] == 1) return x;
  if (isAncestor(centroid) == true) return solve(query2(centroid));
  return solve(parent[centroid]);
}
int main() {
  cin >> n;
  for (int i = 0; i < n - 1; i++) {
    int u, v;
    cin >> u >> v;
    graph[u].push_back(v);
    graph[v].push_back(u);
  }
  DFSInit1(1, -1, 0);
  baseDist = query1(1);
  cout << "! " << solve(1) << '\n';
  cout.flush();
}
