#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 10;
struct edge {
  int nxt, to;
} e[N << 1];
int head[N], pos, n, tp[N], ed[N], son[N], siz[N], anc[N][20], dep[N], tdp;
void dfs1(int u, int fa) {
  int i;
  son[u] = -1;
  siz[u] = 1;
  dep[u] = dep[fa] + 1;
  for (i = head[u]; i; i = e[i].nxt) {
    int v = e[i].to;
    if (v == fa) continue;
    anc[v][0] = u;
    dfs1(v, u);
    siz[u] += siz[v];
    if (son[u] == -1 || siz[son[u]] < siz[v]) son[u] = v;
  }
}
void dfs2(int u, int fa) {
  int i;
  tp[u] = fa;
  if (son[u] == -1) {
    ed[fa] = u;
    return;
  }
  dfs2(son[u], fa);
  for (i = head[u]; i; i = e[i].nxt) {
    int v = e[i].to;
    if (v == anc[u][0] || v == son[u]) continue;
    dfs2(v, v);
  }
}
void add(int u, int v) {
  e[++pos] = (edge){head[u], v};
  head[u] = pos;
}
int T;
int qdp(int u) {
  int a;
  printf("d %d\n", u);
  fflush(stdout);
  scanf("%d", &a);
  if (!a) {
    printf("! %d", u);
    exit(0);
  }
  if (dep[u] - (dep[u] + tdp - a) / 2 == a) T = 1;
  return (dep[u] + tdp - a) >> 1;
}
int main() {
  scanf("%d", &n);
  int i, j;
  for (i = 2; i <= n; ++i) {
    int x, y;
    scanf("%d%d", &x, &y);
    add(x, y);
    add(y, x);
  }
  dfs1(1, 0);
  dfs2(1, 1);
  for (j = 1; j <= 19; ++j)
    for (i = 1; i <= n; ++i) anc[i][j] = anc[anc[i][j - 1]][j - 1];
  printf("d 1\n");
  fflush(stdout);
  scanf("%d", &tdp);
  ++tdp;
  int u = 1;
  int mx = -1;
  while (1) {
    u = ed[u];
    int DEP = qdp(u);
    for (i = 19; i >= 0; --i)
      if (dep[anc[u][i]] >= DEP) u = anc[u][i];
    if (dep[u] == mx) {
      printf("! %d", u);
      return 0;
    }
    mx = dep[u];
    if (T) {
      printf("! %d", u);
      return 0;
    }
    printf("s %d\n", u);
    fflush(stdout);
    scanf("%d", &u);
  }
}
