#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
/**
* Bergen Light Railway - Tree Difference Array + LCA
*/
const int MAXN = 100005;
const int LOGN = 18;
vector<pair<int, int>> adj[MAXN];
int up[MAXN][LOGN], tin[MAXN], tout[MAXN], timer;
int depth[MAXN], edge_id[MAXN];
long long diff[MAXN];
int n, m, k;
void dfs_lca(int u, int p, int d, int id) {
tin[u] = ++timer;
up[u][0] = p;
depth[u] = d;
edge_id[u] = id;
for (int i = 1; i < LOGN; i++)
up[u][i] = up[up[u][i - 1]][i - 1];
for (auto& edge : adj[u]) {
if (edge.first != p) dfs_lca(edge.first, u, d + 1, edge.second);
}
tout[u] = timer;
}
bool is_ancestor(int u, int v) {
return tin[u] <= tin[v] && tout[u] >= tout[v];
}
int get_lca(int u, int v) {
if (is_ancestor(u, v)) return u;
if (is_ancestor(v, u)) return v;
for (int i = LOGN - 1; i >= 0; i--) {
if (!is_ancestor(up[u][i], v)) u = up[u][i];
}
return up[u][0];
}
void dfs_result(int u, int p) {
for (auto& edge : adj[u]) {
if (edge.first != p) {
dfs_result(edge.first, u);
diff[u] += diff[edge.first];
}
}
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
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_lca(1, 1, 0, 0);
for (int i = 0; i < m; i++) {
int s; cin >> s;
vector<int> nodes(s);
for (int j = 0; j < s; j++) cin >> nodes[j];
// Tugunlarni DFS tartibida saralash
sort(nodes.begin(), nodes.end(), [](int a, int b) {
return tin[a] < tin[b];
});
// Steiner Tree qirralarini belgilash
for (int j = 0; j < s; j++) {
int u = nodes[j];
int v = nodes[(j + 1) % s];
int lca = get_lca(u, v);
diff[u]++;
diff[v]++;
diff[lca] -= 2;
}
}
dfs_result(1, 1);
vector<int> result;
for (int i = 2; i <= n; i++) {
// Har bir yo'l 2 marta sanalgan bo'ladi (aylana bo'ylab o'tish hisobiga)
if (diff[i] / 2 >= k) {
result.push_back(edge_id[i]);
}
}
sort(result.begin(), result.end());
cout << result.size() << "\n";
for (int i = 0; i < result.size(); i++) {
cout << result[i] << (i == result.size() - 1 ? "" : " ");
}
cout << endl;
return 0;
}
