#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<int> adj[N];
void dfs(int node, int parent){
tin[node] = ++timer;
up[node][0] = parent;
for(int i = 1; i < 19; i++){
up[node][i] = up[up[node][i - 1]][i - 1];
}
for(auto i : adj[node]){
if(i == parent) continue;
depth[i] = depth[node] + 1;
dfs(i, 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 dfs0(int node, int parent){
for(auto i : adj[node]){
if(i == parent) continue;
dfs0(i, node);
val[node] += val[i];
}
}
int p[N];
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);
adj[v].push_back(u);
edges.push_back({u, v});
}
int r = -1;
for(int i = 1; i <= n; i++){
if(deg[i] == 1){
r = i;
break;
}
}
dfs(r, r);
for(int i = 0; i < m; i++){
int s;
cin >> s;
int mn = n + 1, mx = 0;
while(s--){
int u;
cin >> u;
mn = min(mn, tin[u]);
mx = max(mx, tin[u]);
}
p[mn]++;
p[mx + 1]--;
}
for(int i = 1; i <= n; i++){
p[i] += p[i - 1];
}
// for(int i = 1; i <= n; i++){
// for(int j = 0; j < 18; j++){
// cerr << "up[" << i << "][" << j << "] = " << up[i][j] << endl;
// }
// }
dfs0(1, 1);
vector<int> res;
for(int i = 0; i < n - 1; i++){
auto [u, v] = edges[i];
if(up[u][0] != v) swap(u, v);
int T = min(tin[u], tin[v]);
int T2 = max(tin[u], tin[v]);
if(p[T2] - p[T] >= k){
res.push_back(i + 1);
}
}
cout << res.size() << endl;
for(auto i : res) cout << i << ' ';
cout << endl;
}
