#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define mp make_pair
#define pb push_back
#define ff first
#define ss second
vector<vector<pair<int,int>>> graph(100001);
int parent[100001][20], depth[100001], weight[100001], order[100001];
int tpow(int a) {
int val = 1;
for (int i=0;i<a;i++) {
val *= 2;
} return val;
}
void dfs(int a, int b, int c) {
depth[a] = b;
order[a] = c;
for (pair<int,int> i: graph[a]) {
if (i.ff != parent[a][0]) {
parent[i.ff][0] = a;
c += 1;
dfs(i.ff, b + 1, c);
}
}
}
bool comp(int a, int b) {
return order[a] < order[b];
}
bool compdepth(int a, int b) {
return depth[a] > depth[b];
}
int lca(int a, int b) {
if (depth[a] < depth[b]) {
swap(a, b);
}
int diff = depth[a] - depth[b];
for (int i=19;i>-1;i--) {
if ((diff & tpow(i))) a = parent[a][i];
}
if (a == b) return a;
for (int i=19;i>-1;i--) {
if (parent[a][i] != parent[b][i]) {
a = parent[a][i];
b = parent[b][i];
}
}
return parent[a][0];
}
int main() {
//cin.tie(0)->sync_with_stdio(false);
for (int i=0;i<100001;i++) {
weight[i] = 0;
}
int n, m, k, d1, d2; cin >> n >> m >> k;
for (int i=0;i<n-1;i++) {
cin >> d1 >> d2; d1--; d2--;
graph[d1].push_back(mp(d2, i));
graph[d2].push_back(mp(d1, i));
}
vector<vector<int>> ministers(m);
for (int i=0;i<m;i++) {
cin >> d1;
for (int j=0;j<d1;j++) {
cin >> d2; d2--;
ministers[i].push_back(d2);
}
}
parent[0][0] = 0;
dfs(0, 0, 0);
for (int i=1;i<20;i++) {
for (int j=0;j<n;j++) {
parent[j][i] = parent[parent[j][i - 1]][i - 1];
}
}
//for (int i=0;i<n;i++) {
// cout << i << ' ' << depth[i] << '\n';
//} cout << '\n';
//for (int i=0;i<n;i++) {
// cout << i << ' ' << order[i] << '\n';
//} cout << '\n';
for (int i=0;i<m;i++) {
vector<int> bruh = ministers[i];
sort(bruh.begin(), bruh.end(), comp);
int top = bruh[0];
weight[bruh[0]] += 1;
for (int j=1;j<(int)bruh.size();j++) {
weight[bruh[j]] += 1;
int sus = lca(bruh[j], bruh[j - 1]);
weight[sus] -= 1;
if (depth[sus] < depth[top]) top = sus;
}
weight[top] -= 1;
//for (int i=0;i<n;i++) {
// cout << weight[i] << ' ';
//} cout << '\n';
}
vector<int> botsort;
for (int i=0;i<n;i++) botsort.pb(i);
sort(botsort.begin(), botsort.end(), compdepth);
vector<int> ansvec;
for (int i: botsort) {
for (pair<int,int> j: graph[i]) {
if (j.ff != parent[i][0] && weight[j.ff] >= k) {
ansvec.pb(j.ss);
}
if (j.ff != parent[i][0]) {
weight[i] += weight[j.ff];
}
}
}
cout << ansvec.size() << '\n';
for (int i: ansvec) {
cout << i + 1 << ' ';
}
}
