/*
Reshad sensei tutorial
*/
#pragma GCC optimize("O3", "inline")
#include <bits/stdc++.h>
using namespace std;
#define ins insert
#define pb push_back
#define int long long int
#define pii pair<int, int>
#define endl '\n'
#define drop(x) cout<<(x)<<endl; return;
#define all(x) x.begin(),x.end()
const int mod = 1e9 +7, sze = 1e5+10, inf = 2e18, prime = 23;
vector<int> graph[sze];
int timer;
int L;
int n;
vector<vector<int>> up;
vector<int> giris,cixis;
int depth[sze];
void dfs(int node,int p){
giris[node]=timer++;
if(p!=node){
depth[node]=depth[p]+1;
}
up[node][0]=p;
for(int i=1;i<=L;i++){
up[node][i]=up[up[node][i-1]][i-1];
}
for(auto v:graph[node]){
if(v!=p){
dfs(v,node);
}
}
cixis[node]=timer++;
}
bool checkata(int a,int b){// A, B'nin ATASIMI ?
return (giris[a]<=giris[b] && cixis[a]>=cixis[b]);
}
int ata(int u,int v){
if(checkata(u,v)){
return u;
}
if(checkata(v,u)){
return v;
}
for(int i=L;i>=0;i--){
if(!checkata(up[u][i],v)){
u=up[u][i];
}
}
return up[u][0];
}
void build(int root){
giris.resize(n+1);
cixis.resize(n+1);
timer=0;
L = ceil(log2(n));
up.assign(n+1,vector<int>(L+1));
dfs(root,root);
}
int sub[sze];
int deg[sze];
void dfs2(int node,int p=-1){
for(auto v:graph[node]){
if(v!=p){
dfs2(v,node);
sub[node]+=sub[v];
}
}
}
void mal(){
int m,k;
vector<pair<int,int>> tracks;
cin>>n>>m>>k;
int root = 1;
for(int i=0;i<n-1;i++){
int u,v;cin>>u>>v;
graph[u].pb(v);
graph[v].pb(u);
tracks.pb({u,v});
}
for(int i=1;i<=n;i++){
if(deg[i]==1){
root=i;
break;
}
}
build(root);
vector<int> lst;
int x;
for(int p=0;p<m;p++){
int s;
cin>>s;
lst.clear();
for(int j=0;j<s;j++){
cin>>x;
lst.pb(x);
}
sort(all(lst),[&](int a,int b){
return giris[a]<giris[b];
});
lst.pb(lst[0]);
for(int i=0;i<s;i++){
int a = lst[i];
int b = lst[i+1];
int c = ata(a,b);
sub[a]++;
sub[b]++;
sub[c]-=2;
}
}
dfs2(root);
// for(int i=1;i<=n;i++){
// cout<<i<<" "<<sub[i]<<endl;
// }
set<pair<int,int>> var;
for(int i=1;i<=n;i++){
if(sub[i]>=2*k){
var.insert({min(i,up[i][0]),max(i,up[i][0])});
}
}
vector<int> ans;
for(int i=0;i<n;i++){
int a = tracks[i].first,b = tracks[i].second;
if(var.count({min(a,b),max(a,b)})){
ans.pb(i);
}
}
cout<<ans.size()<<endl;
for(auto v:ans){
cout<<v+1<<" ";
}
cout<<endl;
}
signed main() {
cin.tie(0)->sync_with_stdio(0);
int tt = 1;
// cin>>tt;
while(tt--){
mal();
}
}
