#include <bits/stdc++.h>
#define int long long
#define TASK "test"
#define ll long long
#define fi first
#define sc second
#define ii pair <int, int>
#define iii pair <int, ii>
using namespace std;
const int MAXN = 1e5;
const int INF = 2e9;
const ll LINF = 1e18;
const int LOG = 16;
int n, m, k, cnt = 0;
int tin[MAXN + 5], h[MAXN + 5], p[MAXN + 5][LOG + 5], dp[MAXN + 5], mark[MAXN + 5];
vector <ii> adj[MAXN + 5];
vector <int> new_adj[MAXN + 5];
vector <int> vec, new_vec;
void Dfs(int u, int par) {
tin[u] = ++cnt;
for (auto v : adj[u]) {
if (v.fi == par) continue;
h[v.fi] = h[u] + 1;
p[v.fi][0] = u;
Dfs(v.fi, u);
}
}
void lastDfs(int u, int par) {
for (auto v : adj[u]) {
if (v.fi == par) continue;
lastDfs(v.fi, u);
dp[u] += dp[v.fi];
mark[v.sc] += dp[v.fi];
}
}
void Build_LCA() {
for (int j = 1; j <= LOG; j++)
for (int i = 1; i <= n; i++)
p[i][j] = p[p[i][j - 1]][j - 1];
h[0] = -1;
}
int lca(int u, int v) {
if (h[u] < h[v]) return lca(v, u);
for (int i = LOG; i >= 0; i--) {
if (h[p[u][i]] >= h[v]) u = p[u][i];
}
if (u == v) return u;
for (int i = LOG; i >= 0; i--) {
if (p[u][i] != p[v][i]) {
u = p[u][i];
v = p[v][i];
}
}
return p[u][0];
}
bool cmp(int u, int v) {
return tin[u] <= tin[v];
}
void build_virtual_tree() {
vector <int> stk;
for (int i = 0; i < (int)new_vec.size(); i++) {
while (!stk.empty() and lca(stk.back(), new_vec[i]) != stk.back()) stk.pop_back();
if (!stk.empty()) {
new_adj[new_vec[i]].push_back(stk.back());
new_adj[stk.back()].push_back(new_vec[i]);
}
stk.push_back(new_vec[i]);
}
}
signed main() {
#ifndef ONLINE_JUDGE
// freopen(TASK".inp", "r", stdin);
// freopen(TASK".out", "w", stdout);
#endif
cin.tie(0)->sync_with_stdio(false);
cin >> n >> m >> k;
for (int i = 1; i < n; i++) {
int u, v; cin >> u >> v;
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
Dfs(1, -1);
Build_LCA();
for (int i = 1; i <= m; i++) {
vec.clear();
new_vec.clear();
int x; cin >> x;
for (int j = 1; j <= x; j++) {
int u; cin >> u;
vec.push_back(u);
}
sort(vec.begin(), vec.end(), cmp);
new_vec = vec;
for (int j = 0; j < (int)vec.size() - 1; j++)
new_vec.push_back(lca(vec[j], vec[j + 1]));
sort(new_vec.begin(), new_vec.end(), cmp);
new_vec.resize(unique(new_vec.begin(), new_vec.end()) - new_vec.begin());
build_virtual_tree();
int mi = cnt + 1, root;
for (auto u : new_vec) {
if (tin[u] < mi) {
mi = tin[u];
root = u;
}
}
for (auto u : new_vec) {
if (u != root)
dp[u] += 1 - ((int)new_adj[u].size() - 1);
else
dp[u] += - (int)new_adj[u].size() - 1;
new_adj[u].clear();
}
}
lastDfs(1, -1);
vector <int> ans;
for (int i = 1; i < n; i++) {
if (mark[i] >= k)
ans.push_back(i);
}
cout << (int)ans.size() << '\n';
sort(ans.begin(), ans.end());
for (auto u : ans) cout << u << ' ';
return 0;
}
