#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5+10;
int n, m, k;
int pai[maxn], nivel[maxn], siz[maxn], in[maxn], t;
int chain[maxn], head[maxn], pos[maxn], c, qtd;
int tree[4*maxn], lazy[4*maxn];
map<pair<int,int>,int> edges;
vector<int> grafo[maxn];
void dfs(int u, int p){
siz[u] = 1, in[u] = ++t;
for(int i=0; i<grafo[u].size(); i++){
int v = grafo[u][i];
if(v==p) continue;
pai[v] = u, nivel[v] = nivel[u] + 1;
dfs(v, u);
siz[v] += siz[u];
}
}
void flush(int node, int l, int r){
tree[node] += lazy[node] * (r-l+1);
if(l!=r){
lazy[2*node] += lazy[node];
lazy[2*node+1] += lazy[node];
}
lazy[node] = 0;
}
void update_tree(int node, int tl, int tr, int l, int r, int val){
flush(node, tl, tr);
if(tl > r or tr < l) return;
if(tl >= l and tr <= r){
lazy[node] += val;
flush(node, tl, tr);
return;
}
int mid = (tl + tr) >> 1;
update_tree(2*node, tl, mid, l, r, val), update_tree(2*node+1, mid+1, tr, l, r, val);
tree[node] = tree[2*node] + tree[2*node+1];
}
int query_tree(int node, int tl, int tr, int l, int r){
flush(node, tl, tr);
if(tl > r or tr < l) return 0;
if(tl >= l and tr <= r) return tree[node];
int mid = (tl + tr) >> 1;
return query_tree(2*node, tl, mid, l, r) + query_tree(2*node+1, mid+1, tr, l, r);
}
void hld(int u){
if(!head[c]) head[c] = u;
chain[u] = c, pos[u] = ++qtd;
int maior = -1, id = -1;
for(int i=0; i<grafo[u].size(); i++){
int v = grafo[u][i];
if(v!=pai[u] and siz[v] > maior){
maior = siz[v], id = v;
}
}
if(id!=-1) hld(id);
for(int i=0; i<grafo[u].size(); i++){
int v = grafo[u][i];
if(v!=pai[u] and v!=id){
c++;
hld(v);
}
}
}
int lca(int u, int v){
while(chain[u] != chain[v]){
if(nivel[head[chain[u]]] > nivel[head[chain[v]]]) u = pai[head[chain[u]]];
else v = pai[head[chain[v]]];
}
return (nivel[u] < nivel[v] ? u : v);
}
void update(int u, int v){
int l = lca(u, v);
while(chain[u] != chain[l]){
update_tree(1, 1, n, pos[head[chain[u]]], pos[u], 1);
u = pai[head[chain[u]]];
}
if(u!=l) update_tree(1, 1, n, pos[l]+1, pos[u], 1);
}
int query(int u){
return (query_tree(1, 1, n, pos[u], pos[u]) >= k);
}
bool compara(int u, int v){
return in[u] < in[v];
}
int main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
cin >> n >> m >> k;
int tempo = 0;
for(int i=1; i<n; i++){
int u, v;
cin >> u >> v;
grafo[u].push_back(v);
grafo[v].push_back(u);
edges[{u, v}] = ++tempo;
edges[{v, u}] = tempo;
}
dfs(1, 0);
hld(1);
for(int i=1; i<=m; i++){
int s;
cin >> s;
vector<int> atuais;
int last;
for(int j=1; j<=s; j++){
int u;
cin >> u;
atuais.push_back(u);
if(j==2) last = lca(atuais[j-1], atuais[j-2]);
else if(j>=3) last = lca(last, atuais[j-1]);
}
sort(atuais.begin(), atuais.end(), compara);
for(int j=0; j<atuais.size(); j++){
update(atuais[j], last);
last = atuais[j];
}
}
vector<int> ans;
for(int i=2; i<=n; i++){
if(query(i)){
ans.push_back(edges[{i, pai[i]}]);
}
}
sort(ans.begin(), ans.end());
cout << ans.size() << "\n";
for(int i=0; i<ans.size(); i++){
cout << ans[i] << " ";
}
cout << "\n";
return 0;
}
