#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-8;
const long long inf = 1e9;
const long long mod = 1e9 + 7;
const int maxn = 2e5 + 10;
struct node {
  int d;
  node *to;
} * e[maxn];
char str[20];
int siz[maxn], fa[maxn], dep[maxn], minsiz, root, pre_root, nn;
bool hav[maxn];
void dfs(int d) {
  int maxs = 0;
  node *p = e[d];
  siz[d] = 1;
  while (p) {
    if (fa[d] != p->d && !hav[p->d]) {
      fa[p->d] = d;
      dep[p->d] = dep[d] + 1;
      dfs(p->d);
      siz[d] += siz[p->d];
      maxs = max(maxs, siz[p->d]);
    }
    p = p->to;
  }
  maxs = max(maxs, nn - siz[d]);
  if (maxs < minsiz) minsiz = maxs, root = d;
}
int main() {
  node *p;
  int n, x, y, i, r, dist;
  scanf("%d", &n);
  for (i = 1; i < n; i++) {
    scanf("%d%d", &x, &y);
    p = new node();
    p->d = y;
    p->to = e[x];
    e[x] = p;
    p = new node();
    p->d = x;
    p->to = e[y];
    e[y] = p;
  }
  gets(str);
  printf("d %d\n", 1);
  fflush(stdout);
  scanf("%d", &dist);
  if (dist == 0) {
    printf("! %d\n", 1);
    fflush(stdout);
    return 0;
  }
  nn = n;
  root = 1;
  while (1) {
    pre_root = root;
    dep[pre_root] = 0;
    minsiz = inf;
    dfs(root);
    if (root == pre_root) {
      printf("s %d\n", root);
      fflush(stdout);
      hav[root] = 1;
      scanf("%d", &root);
      dist--;
      if (dist == 0) {
        printf("! %d\n", root);
        fflush(stdout);
        return 0;
      }
      nn = siz[root];
    } else {
      printf("d %d\n", root);
      fflush(stdout);
      scanf("%d", &r);
      if (r == 0) {
        printf("! %d\n", root);
        fflush(stdout);
        return 0;
      }
      hav[root] = 1;
      if (r + dep[root] == dist) {
        printf("s %d\n", root);
        fflush(stdout);
        dist -= dep[root] + 1;
        scanf("%d", &root);
        if (dist == 0) {
          printf("! %d\n", root);
          fflush(stdout);
          return 0;
        }
        nn = siz[root];
      } else {
        nn = siz[pre_root] - siz[root];
        root = pre_root;
      }
    }
  }
  return 0;
}
