#include <bits/stdc++.h>
using namespace std;
#define int long long
#define mp make_pair
#define ii pair <int,int>
const int N = 1e5 + 5 , Lg = 17;
int n , m , k , u , v , P , T , Roto , in[N] , d[N] , x[N] , dp[N] , p[N][Lg] , cnt[N];
vector <ii> adj[N];
vector <int> rt , qu[N];
void dfs(int u){
in[u] = ++ T;
for (int i = 1 ; i < Lg ; i ++) p[u][i] = p[p[u][i-1]][i-1];
for (auto i : adj[u]) if (i.first != p[u][0])
{
p[i.first][0] = u , d[i.first] = d[u] + 1;
dfs(i.first);
}
}
int __lca(int u,int v){
if (d[u] < d[v]) swap(u,v);
for (int i = Lg - 1 ; i >= 0 ; i --) if (d[p[u][i]] >= d[v]) u = p[u][i];
if (u == v) return u;
for (int i = Lg - 1 ; i >= 0 ; i --) if (p[u][i] != p[v][i]) u = p[u][i] , v = p[v][i];
return p[u][0];
}
bool cmp(int& a,int& b){
return in[a] < in[b];
}
void calc(int u){
for (int j = 0 ; j < (int)adj[u].size() ; j ++){
int v = adj[u][j].first , i = adj[u][j].second;
if (v == p[u][0]) continue;
calc(v) , cnt[i] = dp[v] , dp[u] += dp[v];
}
}
signed main(){
cin.tie(0)->sync_with_stdio(0);
cin >> n >> m >> k;
for (int i = 1 ; i < n ; i ++) cin >> u >> v , adj[u].push_back(mp(v,i)) , adj[v].push_back(mp(u,i));
dfs(1);
for (int i = 1 ; i <= m ; i ++){
cin >> x[i];
qu[i].resize(x[i]);
for (int j = 0 ; j < x[i] ; j ++) cin >> qu[i][j];
sort(qu[i].begin() , qu[i].end() , cmp);
Roto = qu[i][0];
for (int j = 1 ; j < x[i] ; j ++){
P = __lca(qu[i][j-1] , qu[i][j]);
dp[qu[i][j]] ++ , dp[P] --;
if (d[Roto] > d[P]) dp[Roto] ++ , dp[P] -- , Roto = P;
}
}
calc(1);
for (int i = 1 ; i < n ; i ++) if (cnt[i] >= k) rt.push_back(i);
cout << rt.size() << '\n';
sort(rt.begin() , rt.end());
for (auto u : rt) cout << u << ' ';
return 0;
}
