#include <bits/stdc++.h>
using namespace std;
const int N = 1e5;
vector<pair<int, int>> adj[N + 8];
int pe_id[N + 8];
int h[N + 8], tin[N + 8], tout[N + 8];
pair<int, int> euler[N * 2 + 8];
int upd[N + 8];
void add_edge(int u, int v, int id) {adj[u].push_back({v, id}); adj[v].push_back({u, id});}
int timer = 0;
void DFS_EulerTour(int u, int p) {
int v, id;
tin[u] = ++timer; euler[timer] = {h[u], u};
for (pair<int, int> E : adj[u]) if (E.first != p) {
tie(v, id) = E; h[v] = h[u] + 1; pe_id[v] = id;
DFS_EulerTour(v, u); euler[++timer] = {h[u], u};
}
tout[u] = timer;
}
pair<int, int> SpT[N * 2 + 8][20];
int lg;
void build() {
for (lg = 0; lg <= __lg(timer); ++lg) for (int i = 1; i + (1 << lg) - 1 <= timer; ++i)
if (!lg) SpT[i][lg] = euler[i];
else SpT[i][lg] = min(SpT[i][lg - 1], SpT[i + (1 << (lg - 1))][lg - 1]);
}
pair<int, int> range_min(int l, int r) {
lg = __lg(r - l + 1);
return min(SpT[l][lg], SpT[r + 1 - (1 << lg)][lg]);
}
int LCA(int u, int v) {
if (tin[u] > tin[v]) swap(u, v);
return range_min(tin[u], tin[v]).second;
}
bool custom(int u, int v) {return tin[u] < tin[v];}
void DFS(int u, int p) {
for (pair<int, int> E : adj[u]) if (E.first != p) {
DFS(E.first, u);
upd[u] += upd[E.first];
}
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n, q, k, u, v; cin >> n >> q >> k;
for (int i = 1; i < n; ++i) cin >> u >> v, add_edge(u, v, i);
DFS_EulerTour(1, 0); build();
int sz; vector<int> nodes;
while (q--) {
cin >> sz; nodes.clear();
while (sz--) cin >> u, nodes.push_back(u);
sort(nodes.begin(), nodes.end(), custom); nodes.push_back(nodes[0]);
for (int i = 0; i + 1 < nodes.size(); ++i) {
++upd[nodes[i]]; ++upd[nodes[i + 1]];
upd[LCA(nodes[i], nodes[i + 1])] -= 2;
}
// for (int i : nodes) cout << i << ' ';
// cout << '\n';
}
DFS(1, 0); vector<int> ans;
for (int i = 2; i <= n; ++i) if (upd[i] >= k + k) ans.push_back(pe_id[i]);
sort(ans.begin(), ans.end()); cout << ans.size() << '\n';
for (int i : ans) cout << i << ' ';
}
