#include<bits/stdc++.h>
using namespace std;
int main(){
int n,m,k;
cin>>n>>m>>k;
vector<int>adj[n+5];
vector<int>a(n+5),b(n+5);
for(int i=0;i<n-1;i++){
int u,v;cin>>u>>v;
a[i]=u;b[i]=v;
adj[u].push_back(v);
adj[v].push_back(u);
}
int root;
for(int i=1;i<=n;i++){
if(adj[i].size()==1){
root=i;
}
}
queue<int>q;
q.push(root);
vector<bool>vis(n+5);
vector<int>c;
while(q.size()){
int x=q.front();
q.pop();
vis[x]=1;
c.push_back(x);
for(auto i:adj[x]){
if(!vis[i]){
q.push(i);
}
}
}
map<int,int>mp;
for(int i=0;i<n;i++){
mp[c[i]]=i;
}
vector<int>p(n);
while(m--){
int k;cin>>k;
vector<int>v(k);
for(auto &i:v)cin>>i;
int l=1e9,r=-1;
for(auto i:v){
l=min(l,mp[i]);
r=max(r,mp[i]);
}
p[l]++;
if(r+1<n){
p[r+1]--;
}
}
map<pair<int,int>,bool>e;
for(int i=1;i<n;i++){
p[i]+=p[i-1];
if(p[i]>=k && p[i-1]>=k){
e[{c[i],c[i-1]}]=1;
e[{c[i-1],c[i]}]=1;
}
}
vector<int>d;
for(int i=0;i<n-1;i++){
if(e[{a[i],b[i]}]){
d.push_back(i+1);
}
}
cout<<d.size()<<endl;
for(auto i:d)cout<<i<<" ";
}
