#include <bits/stdc++.h>
using namespace std;
const int kN = 1e5;
const int kLog = 16;
int timer, tin[1 + kN], tout[1 + kN], depth[1 + kN], edge[1 + kN], dp[1 + kN], lg2[1 + kN], anc[1 + kN][1 + kLog];
vector<pair<int, int>> g[1 + kN];
void precalc() {
for (int i = 2; i < kN; ++i) {
lg2[i] = lg2[i / 2] + 1;
}
}
void dfs1(int u) {
tin[u] = ++timer;
for (int i = 1; i <= kLog; ++i) {
anc[u][i] = anc[anc[u][i - 1]][i - 1];
if (anc[u][i] == 0) {
break;
}
}
for (auto it : g[u]) {
int v, index;
tie(v, index) = it;
if (v != anc[u][0]) {
anc[v][0] = u;
depth[v] = depth[u] + 1;
edge[v] = index;
dfs1(v);
}
}
tout[u] = timer;
}
void dfs2(int u) {
for (auto it : g[u]) {
int v = it.first;
if (v != anc[u][0]) {
dfs2(v);
dp[u] += dp[v];
}
}
}
bool isAncestor(int u, int v) {
return tin[u] <= tin[v] && tout[v] <= tout[u];
}
int getLca(int u, int v) {
if (depth[u] < depth[v]) {
swap(u, v);
}
if (isAncestor(v, u)) {
return v;
}
for (int i = lg2[depth[v]]; i >= 0; --i) {
if (anc[v][i] && !isAncestor(anc[v][i], u)) {
v = anc[v][i];
}
}
return anc[v][0];
}
void testCase() {
int n, m, k;
cin >> n >> m >> k;
for (int i = 1; i < n; ++i) {
int u, v;
cin >> u >> v;
g[u].emplace_back(v, i);
g[v].emplace_back(u, i);
}
dfs1(1);
for (int i = 0; i < m; ++i) {
int N;
cin >> N;
vector<int> nodes(N);
for (int i = 0; i < N; ++i) {
cin >> nodes[i];
}
sort(nodes.begin(), nodes.end(), [&](const int &x, const int &y) -> bool {
return tin[x] < tin[y];
});
nodes.emplace_back(nodes[0]);
for (int i = 1; i <= N; ++i) {
int lca = getLca(nodes[i - 1], nodes[i]);
dp[nodes[i - 1]] += 1;
dp[nodes[i]] += 1;
dp[lca] -= 2;
}
}
dfs2(1);
vector<int> sol;
for (int v = 2; v <= n; ++v) {
if (dp[v] >= 2 * k) {
sol.emplace_back(edge[v]);
}
}
sort(sol.begin(), sol.end());
cout << sol.size() << '\n';
for (int index : sol) {
cout << index << ' ';
}
cout << '\n';
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
precalc();
int tests = 1;
for (int tc = 0; tc < tests; ++tc) {
testCase();
}
return 0;
}
