#include <bits/stdc++.h>
using namespace std;
#define pii pair <int, int>
#define fi first
#define se second
#define mp make_pair
const int NM = 1e5;
int n, m, k, t = 0, u[NM+5], v[NM+5], st[NM+5], en[NM+5];
vector <int> adj[NM+5], s[NM+5];
vector <pii> A;
int vertex_id[NM+5], edge_id[NM+5], set_id[NM+5];
int bit[NM+5], f[NM+5], ptr[NM+5], g[NM+5];
vector <int> ans;
void DFS(int u, int p){
st[u] = ++t;
for (int i = 0; i < adj[u].size(); i++){
int v = adj[u][i];
if (v == p) continue;
DFS(v, u);
}
en[u] = t;
}
bool vertex_cmp(int x, int y){
return st[x] < st[y];
}
bool set_cmp(int x, int y){
return st[s[x][0]] < st[s[y][0]];
}
bool other_cmp(pii a, pii b){
return st[a.fi] < st[b.fi];
}
void update(int p, int v){
while (p <= n){
bit[p] += v;
p += p & (-p);
}
}
int get(int p){
int res = 0;
while (p > 0){
res += bit[p];
p -= p & (-p);
}
return res;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> m >> k;
for (int i = 1; i < n; i++){
cin >> u[i] >> v[i];
adj[u[i]].push_back(v[i]);
adj[v[i]].push_back(u[i]);
vertex_id[i+1] = i+1;
}
DFS(1, -1);
sort(vertex_id+2, vertex_id+1+n, vertex_cmp);
for (int i = 1; i <= m; i++){
int t, v; cin >> t;
while (t--){
cin >> v;
s[i].push_back(v);
A.push_back(mp(v, i));
}
sort(s[i].begin(), s[i].end(), vertex_cmp);
set_id[i] = i;
}
sort(set_id+1, set_id+1+m, set_cmp);
int j = m;
for (int ii = n; ii >= 2; ii--){
int i = vertex_id[ii];
while (j >= 1 && st[s[set_id[j]][0]] >= st[i]){
update(st[s[set_id[j]].back()], 1);
j--;
}
f[i] = m-get(en[i]);
}
sort(A.begin(), A.end(), other_cmp);
for (int i = 1; i <= m; i++) ptr[i] = s[i].size();
memset(bit, 0, sizeof(bit));
j = A.size()-1;
for (int ii = n; ii >= 2; ii--){
int i = vertex_id[ii];
while (j >= 0 && st[A[j].fi] >= st[i]){
if (ptr[A[j].se] < s[A[j].se].size()) update(st[s[A[j].se][ptr[A[j].se]]], -1);
ptr[A[j].se]--;
if (ptr[A[j].se] >= 0) update(st[A[j].fi], 1);
j--;
}
g[i] = get(en[i]);
}
for (int i = 1; i < n; i++){
if (st[u[i]] > st[v[i]]) swap(u[i], v[i]);
if (f[v[i]]+g[v[i]]-m >= k) ans.push_back(i);
}
cout << ans.size() << '\n';
for (int i = 0; i < ans.size(); i++) cout << ans[i] << ' ';
return 0;
}
