#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline bool chkmin(T &x, T y) {
  return x > y ? x = y, 1 : 0;
}
template <typename T>
inline bool chkmax(T &x, T y) {
  return x < y ? x = y, 1 : 0;
}
template <typename T>
inline void read(T &x) {
  char ch = getchar();
  int f = 1;
  x = 0;
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') x = x * 10 + ch - '0', ch = getchar();
  x *= f;
}
template <typename T, typename... Args>
inline void read(T &x, Args &...args) {
  read(x), read(args...);
}
int n, dep[200050], fa[200050], size[200050], ms[200050], rt, Size, vis[200050];
int Dep;
vector<int> adj[200050];
void getd(int u) {
  for (int v : adj[u])
    if (v != fa[u]) fa[v] = u, dep[v] = dep[u] + 1, getd(v);
}
void getrt(int u, int f) {
  size[u] = 1, ms[u] = 0;
  for (int v : adj[u])
    if (v != f && !vis[v])
      getrt(v, u), chkmax(ms[u], size[v]), size[u] += size[v];
  chkmax(ms[u], Size - size[u]);
  if (ms[u] < ms[rt]) rt = u;
}
int askd(int u) {
  int x;
  cout << "d " << u << endl, fflush(stdout);
  cin >> x;
  return x;
}
int asku(int u) {
  int x;
  cout << "s " << u << endl, fflush(stdout);
  cin >> x;
  return x;
}
void Answer(int u) {
  cout << "! " << u << endl, fflush(stdout);
  exit(0);
}
void solve(int u) {
  getrt(u, 0), vis[u] = 1;
  int _d1 = askd(u), v;
  if (_d1 == 0) Answer(u);
  if (_d1 + dep[u] == Dep)
    v = asku(u);
  else
    v = fa[u];
  Size = size[v], rt = 0, getrt(v, 0), solve(rt);
}
int main() {
  read(n);
  int u, v;
  for (register int i = 1; i <= n - 1; ++i)
    read(u, v), adj[u].push_back(v), adj[v].push_back(u);
  getd(1), Dep = askd(1);
  Size = n, ms[0] = 1e9, rt = 0, getrt(1, 0), solve(rt);
  return 0;
}
