#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
const long long int LINF = 0x3f3f3f3f3f3f3f3fll;
const int MAX = (int)2e5 + 10;
int queryd(int u) {
  cout << "d " << u + 1 << endl;
  cout.flush();
  int d;
  cin >> d;
  return d;
}
int querys(int u) {
  cout << "s " << u + 1 << endl;
  cout.flush();
  int d;
  cin >> d;
  return d - 1;
}
void resp(int x) {
  cout << "! " << x + 1 << endl;
  cout.flush();
}
int n, root, cent;
vector<int> g[MAX];
bool block[MAX];
int sizet[MAX], dist[MAX];
void get_dist(int u, int p, int d) {
  dist[u] = d;
  for (int e : g[u])
    if (e != p and !block[e]) {
      get_dist(e, u, d + 1);
    }
}
int get_size(int u, int p) {
  sizet[u] = 1;
  for (int e : g[u])
    if (e != p and !block[e]) {
      sizet[u] += get_size(e, u);
    }
  return sizet[u];
}
int centroid(int u, int p, int size) {
  for (int e : g[u])
    if (e != p and !block[e]) {
      if (sizet[e] > size / 2) {
        return centroid(e, u, size);
      }
    }
  return u;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  ;
  cin >> n;
  for (int i = 0; i < n - 1; i++) {
    int a, b;
    cin >> a >> b;
    a--, b--;
    g[a].push_back(b);
    g[b].push_back(a);
  }
  for (int i = 0; i < n; i++) block[i] = false;
  root = 0;
  int dx = queryd(root);
  while (1) {
    if (sizet[root] == 1 or dx == 0) {
      break;
    }
    get_size(root, root);
    cent = centroid(root, root, sizet[root]);
    get_dist(root, root, 0);
    if (cent != root) {
      int dcx = queryd(cent);
      if (dcx == 0) {
        root = cent;
        break;
      }
      if (dx == dcx + dist[cent]) {
        root = querys(cent);
        dx = dcx - 1;
      } else {
        root = querys(root);
        dx--;
      }
    } else {
      root = querys(root);
      dx--;
    }
    block[cent] = true;
  }
  resp(root);
  return 0;
}
