#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10, LG = 20;
int n, m, k, par[N][LG], h[N], cnt[N], st[N];
vector<int> adj[N], tr, ans;
pair<int, int> edge[N];
void dfs(int u) {
st[u] = tr.size();
tr.push_back(u);
for (int v: adj[u])
if (v != par[u][0]) {
h[v] = h[u] + 1, par[v][0] = u;
dfs(v);
}
}
void pre() {
par[0][0] = n;
dfs(0);
for (int j = 1; j < LG; j++)
for (int i = 0; i < n; i++)
if (h[i] >= (1 << j))
par[i][j] = par[par[i][j - 1]][j - 1];
}
int lca(int u, int v) {
if (h[u] < h[v]) swap(u, v);
for (int i = LG - 1; i >= 0; i--)
if (h[u] - (1 << i) >= h[v])
u = par[u][i];
if (u == v) return u;
for (int i = LG - 1; i >= 0; i--)
if (h[u] >= (1 << i) && par[u][i] != par[v][i])
u = par[u][i], v = par[v][i];
return par[u][0];
}
void add_path(int u, int v) {
// cout << u << ' ' << v << " : " << lca(u, v) << '\n';
cnt[u]++;
cnt[v]++;
cnt[lca(u, v)] -= 2;
}
void dfs_relax(int u) {
for (int v: adj[u])
if (v != par[u][0]) {
dfs_relax(v);
cnt[u] += cnt[v];
}
// cout << u + 1 << ' ' << cnt[u] << '\n';
}
void input() {
cin >> n >> m >> k;
for (int i = 0; i < n - 1; i++) {
int u, v;
cin >> u >> v;
u--, v--;
adj[u].push_back(v);
adj[v].push_back(u);
edge[i] = {u, v};
}
}
void solve() {
pre();
for (int i = 0; i < m; i++) {
int sz;
cin >> sz;
vector<int> vec(sz);
for (int j = 0; j < sz; j++) {
cin >> vec[j];
vec[j]--;
}
sort(vec.begin(), vec.end(), [](int p1, int p2) {
return st[p1] < st[p2];
});
for (int j = 1; j < sz; j++)
add_path(vec[j], vec[j - 1]);
add_path(vec[0], vec[sz - 1]);
}
dfs_relax(0);
for (int i = 0; i < n - 1; i++) {
if (h[edge[i].first] > h[edge[i].second])
swap(edge[i].first, edge[i].second);
if (cnt[edge[i].second] >= 2 * k)
ans.push_back(i + 1);
}
}
void output() {
cout << ans.size() << '\n';
for (int u: ans)
cout << u << ' ';
}
int main() {
ios:: sync_with_stdio(0), cin.tie(0), cout.tie(0);
input();
solve();
output();
}
