#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <set>
#include <map>
#define INF 1e9
using namespace std;
typedef long long ll;
vector<pair<int,int>>adj[100005];
int d[100005], p[100005][20], tin[100005], tout[100005], dp[100005], pos[100005], x[100005];
int timer = 0, n = 0, m = 0, k = 0;
void dfs(int s, int e) {
tin[s] = ++timer;
for (int i = 1; i <= 18; i++) {
p[s][i] = p[p[s][i - 1]][i - 1];
}
for (auto u : adj[s]) {
if (u.first == e) continue;
d[u.first] = d[s] + 1;
p[u.first][0] = s;
pos[u.first] = u.second;
dfs(u.first, s);
}
tout[s] = timer;
}
int lca(int a, int b) {
if (d[a] > d[b]) swap(a, b);
int dis = d[b] - d[a];
for (int i = 0; i <= 18; i++) {
if (dis & (1 << i)) b = p[b][i];
}
if (a == b) return a;
for (int i = 18; i >= 0; i--) {
if (p[a][i] != p[b][i]) {
a = p[a][i];
b = p[b][i];
}
}
return p[a][0];
}
bool comp(int x, int y) {
return tin[x] < tin[y];
}
void dfs1(int s, int e) {
for (auto u : adj[s]) {
if (u.first == e) continue;
dfs1(u.first, s);
dp[s] += dp[u.first];
}
if (dp[s] >= 2 * k) {
x[pos[s]] = true;
//cout << pos[s] << "\n";
}
}
void solve()
{
cin >> n >> m >> k;
for (int i = 1; i <= n - 1; i++) {
int u, v; cin >> u >> v;
adj[u].push_back({v, i });
adj[v].push_back({u, i});
}
dfs(1, 0);
for (int i = 1; i <= m; i++) {
int s; cin >> s;
vector<int>v(s);
for (int i = 0; i < s; i++) cin >> v[i];
sort(v.begin(), v.end(), comp);
for (int i = 0; i < s; i++) {
dp[v[i]]++;
dp[v[(i + 1) % s]]++;
dp[lca(v[i], v[(i + 1) % s])] -= 2;
}
}
dfs1(1, 0);
int ans = 0;
for (int i = 1; i <= n - 1; i++) { if (x[i]) ++ans; }
cout << ans << "\n";
for (int i = 1; i <= n - 1; i++) {
if(x[i])cout << i << " ";
}
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
int t = 1;// cin>>t;
while (t--) solve();
return 0;
}
