#include <bits/stdc++.h>
using namespace std;
#define cerr cerr << "DEBUG "
constexpr int N = 1e5 + 10, M = 5e4 + 10;
int n, k, m, pe[N], sz[N];
int init[N], cnt[M], cnt0, cntf;
vector<int> *st[N];
vector<int> col[N], ge[N], g[N], ans;
void prep(int v, int p, int pi) {
pe[v] = pi;
int i = 0;
sz[v] = 1;
for (auto &u : g[v]) {
if (u != p) {
prep(u, v, ge[v][i]);
sz[v] += sz[v];
}
++i;
}
}
void dfs(int v, int p, bool keep) {
int bg = -1, bgs = 0;
for (auto &u : g[v]) {
if (u != p && sz[u] > bgs) {
bgs = sz[u];
bg = u;
}
}
if (bg == -1) {
st[v] = new vector<int>();
st[v]->push_back(v);
} else {
for (auto &u : g[v]) {
if (u != p && u != bg) {
dfs(u, v, false);
}
}
dfs(bg, v, true);
st[v] = st[bg];
st[v]->push_back(v);
for (auto &u : g[v]) {
if (u != p && u != bg) {
for (auto &w : *st[u]) {
st[v]->push_back(w);
for (auto &c : col[w]) {
if (++cnt[c] == init[c]) {
cntf++;
}
if (cnt[c] == 1) {
cnt0--;
}
}
}
delete st[u];
}
}
}
for (auto &c : col[v]) {
if (++cnt[c] == init[c]) {
cntf++;
}
if (cnt[c] == 1) {
cnt0--;
}
}
if (m - cnt0 - cntf >= k) {
ans.push_back(pe[v]);
}
//cerr << v << ' ' << cnt0 << ' ' << cntf << '\n';
if (!keep) {
for (auto &u : *st[v]) {
for (auto &c : col[u]) {
if (--cnt[c] == 0) {
cnt0++;
}
if (cnt[c] == init[c] - 1) {
cntf--;
}
}
}
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> m >> k;
for (int i = 0; i < n - 1; ++i) {
int v, u;
cin >> v >> u;
--v, --u;
g[v].push_back(u);
g[u].push_back(v);
ge[v].push_back(i);
ge[u].push_back(i);
}
for (int i = 0; i < m; ++i) {
int s;
cin >> s;
cnt[i] = 0;
init[i] = s;
if (!s) {
++cntf;
}
++cnt0;
while (s--) {
int v;
cin >> v;
--v;
col[v].push_back(i);
}
}
prep(0, -1, -1);
dfs(0, -1, true);
sort(ans.begin(), ans.end());
cout << ans.size() << '\n';
for (auto &e : ans) {
cout << e + 1 << ' ';
}
}
