#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10;
int n, m, k, up[N][19], depth[N], val[N], tin[N], timer, deg[N];
vector<pair<int,int>> adj[N];
pair<int,int> par[N];
bool marked[N];
void dfs(int node, int parent){
up[node][0] = parent;
for(int i = 1; i < 19; i++){
up[node][i] = up[up[node][i - 1]][i - 1];
}
for(auto [u, i] : adj[node]){
if(u == parent) continue;
depth[u] = depth[node] + 1;
par[u] = {node, i};
dfs(u, node);
}
}
int lca(int u, int v){
if(depth[u] < depth[v]) swap(u, v);
int d = depth[u] - depth[v];
for(int i = 0; i < 19; i++){
if(d & (1 << i)){
u = up[u][i];
}
}
if(u == v) return u;
for(int i = 18; i >= 0; i--){
if(up[u][i] != up[v][i]){
u = up[u][i];
v = up[v][i];
}
}
return up[u][0];
}
void upd(int node, int p){
while(node != p){
marked[par[node].second] = 1;
node = par[node].first;
}
}
int main(){
cin >> n >> m >> k;
vector<pair<int,int>> edges;
for(int i = 1; i < n; i++){
int u, v;
cin >> u >> v;
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
dfs(1, 1);
for(int i = 0; i < m; i++){
int s;
cin >> s;
vector<int> v;
while(s--){
int u;
cin >> u;
v.push_back(u);
}
int l = v[0];
for(auto j : v) l = lca(l, j);
for(auto j : v){
upd(j, l);
}
for(int j = 1; j < n; j++){
val[j] += marked[j];
marked[j] = 0;
}
}
// for(int i = 1; i <= n; i++){
// for(int j = 0; j < 18; j++){
// cerr << "up[" << i << "][" << j << "] = " << up[i][j] << endl;
// }
// }
vector<int> res;
for(int i = 0; i < n - 1; i++){
if(val[i + 1] >= k){
res.push_back(i + 1);
}
}
cout << res.size() << endl;
for(auto i : res) cout << i << ' ';
cout << endl;
}
