#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
const int MAXN = 2e5 + 10;
int n, dx;
int chain_id[MAXN], ssize[MAXN], parent[MAXN], depth[MAXN];
vector<int> v[MAXN], chain[MAXN];
void dfs(int node, int dad) {
  ssize[node] = 1;
  parent[node] = dad;
  for (int nxt : v[node]) {
    if (nxt == dad) continue;
    depth[nxt] = depth[node] + 1;
    dfs(nxt, node);
    ssize[node] += ssize[nxt];
  }
}
void hld(int node, int dad, int cid) {
  chain_id[node] = cid;
  chain[cid].push_back(node);
  int maks = -1;
  for (int nxt : v[node]) {
    if (nxt == dad) continue;
    if (maks == -1 || ssize[nxt] > ssize[maks]) maks = nxt;
  }
  if (maks == -1) return;
  hld(maks, node, cid);
  for (int nxt : v[node]) {
    if (nxt == dad || nxt == maks) continue;
    hld(nxt, node, nxt);
  }
}
int get_distance(int x) {
  int ret;
  printf("d %d\n", x + 1);
  fflush(stdout);
  scanf("%d", &ret);
  return ret;
}
int get_next(int x) {
  int ret;
  printf("s %d\n", x + 1);
  fflush(stdout);
  scanf("%d", &ret);
  return ret - 1;
}
int main(void) {
  scanf("%d", &n);
  for (int i = 0; i < n - 1; ++i) {
    int a, b;
    scanf("%d%d", &a, &b);
    --a;
    --b;
    v[a].push_back(b);
    v[b].push_back(a);
  }
  dfs(0, -1);
  hld(0, -1, 0);
  dx = get_distance(0);
  int root = 0, dist = dx;
  while (dist > 0) {
    int nxt = get_next(root);
    if (chain_id[nxt] != chain_id[root]) {
      root = nxt;
      --dist;
      continue;
    }
    int B = chain[chain_id[root]].back();
    int dist_b = get_distance(B);
    int dy = (depth[B] + dx - dist_b) / 2;
    dist -= dy - depth[root];
    root = chain[chain_id[root]][dy - depth[root]];
  }
  printf("! %d\n", root + 1);
  fflush(stdout);
  return 0;
}
