#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 100'000 + 10;
const int MAX_LG = 17;
int n, m, k, st[MAX_N], ft[MAX_N], h[MAX_N], par[MAX_N][MAX_LG], dp[MAX_N];
vector<pair<int, int>> adj[MAX_N];
vector<int> ans;
int vpar[MAX_N];
vector<int> vadj[MAX_N];
void pre_dfs(int u) {
static int time = 0;
st[u] = time++;
for (int i = 1; i < MAX_LG; ++i) {
par[u][i] = par[par[u][i - 1]][i - 1];
}
for (auto [v, e] : adj[u]) {
if (v != par[u][0]) {
par[v][0] = u;
h[v] = h[u] + 1;
pre_dfs(v);
}
}
ft[u] = time;
}
int get_lca(int u, int v) {
if (h[u] < h[v]) swap(u, v);
for (int i = 0, diff = h[u] - h[v]; diff != 0; ++i, diff >>= 1) {
if (diff & 1) u = par[u][i];
}
if (u == v) return u;
for (int i = MAX_LG - 1; i >= 0; --i) {
if (par[u][i] != par[v][i]) {
u = par[u][i];
v = par[v][i];
}
}
return par[u][0];
}
void add_dfs(int u) {
dp[u] -= int(vadj[u].size()) - 1;
for (int v : vadj[u]) {
add_dfs(v);
}
}
void final_dfs(int u) {
for (auto [v, e] : adj[u]) {
if (v != par[u][0]) {
final_dfs(v);
dp[u] += dp[v];
if (dp[v] >= k) {
ans.push_back(e);
}
}
}
}
int main() {
cin >> n >> m >> k;
for (int e = 1, u, v; e <= n - 1; ++e) {
cin >> u >> v;
adj[u].push_back({v, e});
adj[v].push_back({u, e});
}
pre_dfs(1);
while (m--) {
int s;
cin >> s;
vector<int> V;
for (int i = 0; i < s; ++i) {
int v;
cin >> v;
V.push_back(v);
}
sort(V.begin(), V.end(), [&] (int u, int v) { return st[u] < st[v]; });
for (int i = 0; i + 1 < s; ++i) {
V.push_back(get_lca(V[i], V[i + 1]));
}
sort(V.begin(), V.end(), [&] (int u, int v) { return st[u] < st[v]; });
V.erase(unique(V.begin(), V.end()), V.end());
for (int i = 1; i < V.size(); ++i) {
vpar[V[i]] = V[i - 1];
while (ft[vpar[V[i]]] < ft[V[i]]) {
vpar[V[i]] = vpar[vpar[V[i]]];
}
vadj[vpar[V[i]]].push_back(V[i]);
}
add_dfs(V[0]);
--dp[V[0]];
for (int v : V) {
vpar[v] = 0;
vadj[v].clear();
}
}
final_dfs(1);
cout << ans.size() << '\n';
sort(ans.begin(), ans.end());
for (int e : ans) {
cout << e << ' ';
}
cout << '\n';
}
