#include <bits/stdc++.h>
using namespace std;
template <class T>
void _R(T &x) {
  cin >> x;
}
void _R(int &x) { scanf("%d", &x); }
void _R(long long &x) { scanf("%lld", &x); }
void _R(double &x) { scanf("%lf", &x); }
void _R(char &x) { scanf(" %c", &x); }
void _R(char *x) { scanf("%s", x); }
void R() {}
template <class T, class... U>
void R(T &head, U &...tail) {
  _R(head);
  R(tail...);
}
template <class T>
void _W(const T &x) {
  cout << x;
}
void _W(const int &x) { printf("%d", x); }
void _W(const long long &x) { printf("%lld", x); }
void _W(const double &x) { printf("%.16f", x); }
void _W(const char &x) { putchar(x); }
void _W(const char *x) { printf("%s", x); }
template <class T, class U>
void _W(const pair<T, U> &x) {
  _W(x.first);
  putchar(' ');
  _W(x.second);
}
template <class T>
void _W(const vector<T> &x) {
  for (auto i = x.begin(); i != x.end(); _W(*i++))
    if (i != x.cbegin()) putchar(' ');
}
void W() {}
template <class T, class... U>
void W(const T &head, const U &...tail) {
  _W(head);
  putchar(sizeof...(tail) ? ' ' : '\n');
  W(tail...);
}
int MOD = 1e9 + 7;
void ADD(long long &x, long long v) {
  x = (x + v) % MOD;
  if (x < 0) x += MOD;
}
const int SIZE = 1e6 + 10;
int lv[SIZE], lat[SIZE];
vector<int> e[SIZE];
int can[SIZE];
int AA;
void dfs0(int x, int lt, int v) {
  lv[x] = v;
  for (int y : e[x]) {
    if (y == lt) continue;
    lat[y] = x;
    dfs0(y, x, v + 1);
  }
}
int target;
int cnt(int x, int lt, int dd) {
  if (!dd) {
    target = x;
    return 1;
  }
  int ret = 0;
  for (int y : e[x]) {
    if (y == lt) continue;
    ret += cnt(y, x, dd - 1);
  }
  return ret;
}
int dp[SIZE];
int dfs2(int x, int lt, int dd) {
  if (!dd) {
    dp[x] = can[x];
    return -1;
  }
  dp[x] = 0;
  for (int y : e[x]) {
    if (y == lt) continue;
    int now = dfs2(y, x, dd - 1);
    if (now != -1) return now;
    dp[x] += dp[y];
    if (dp[x] >= (AA + 1) / 2) return x;
  }
  return -1;
}
void clear(int x, int lt, int dd) {
  if (!dd) {
    if (can[x]) {
      can[x] = 0;
      AA--;
    }
    return;
  }
  for (int y : e[x]) {
    if (y == lt) continue;
    clear(y, x, dd - 1);
  }
}
void clear2(int x, int lt, int stop, int dd) {
  if (x == stop) return;
  if (!dd) {
    if (can[x]) {
      can[x] = 0;
      AA--;
    }
    return;
  }
  for (int y : e[x]) {
    if (y == lt) continue;
    clear2(y, x, stop, dd - 1);
  }
}
int find_answer() {
  for (int i = (1); i <= (SIZE); ++i) {
    if (can[i]) return i;
  }
  return -1;
}
int qq(int x, int dd) {
  if (AA == 1) {
    return find_answer();
  }
  if (!dd) return x;
  int qx = dfs2(x, lat[x], dd);
  if (qx != x) {
    W("d", qx);
    fflush(stdout);
    int v;
    R(v);
    if (lv[qx] + v != lv[x] + dd) {
      clear(qx, lat[qx], lv[x] + dd - lv[qx]);
      qx = x;
    } else {
      clear2(x, lat[x], qx, dd);
    }
  }
  if (AA == 1) {
    return find_answer();
  }
  W("s", qx);
  fflush(stdout);
  int v;
  R(v);
  clear2(x, lat[x], v, dd);
  return qq(v, dd - (lv[v] - lv[x]));
}
int main() {
  int n;
  R(n);
  for (int i = (1); i < (n); ++i) {
    int x, y;
    R(x, y);
    e[x].push_back(y);
    e[y].push_back(x);
  }
  dfs0(1, 1, 0);
  int now = 1, dd;
  W("d", now);
  fflush(stdout);
  R(dd);
  for (int i = (1); i <= (n); ++i) {
    if (lv[i] == dd) {
      can[i] = 1;
      AA++;
    }
  }
  W("!", qq(1, dd));
  return 0;
}
