#include <bits/stdc++.h>
using namespace std;
int const MAX=2e5+5;
int const LOG=20;
int n,m,k;
vector<int>tree[MAX];
int euler[MAX];
int pos[MAX];
int h[MAX];
int rmq[MAX][LOG];
int logar[MAX];
int used[MAX];
int query[MAX];
struct edge{
int u,v;
}edg[MAX];
void read(){
cin>>n>>m>>k;
int i;
for(i=1;i<n;++i){
int u,v;
cin>>u>>v;
tree[u].push_back(v);
tree[v].push_back(u);
edg[i]={u,v};
}
}
void dfs(int nod,int tata){
static int time=0;
euler[++time]=nod;
pos[nod]=time;
for(auto fiu : tree[nod])
if(fiu!=tata){
h[fiu]=h[nod]+1;
dfs(fiu,nod);
euler[++time]=nod;
}
}
void get_rmq(){
int i,j;
for(i=1;i<2*n;++i)
rmq[i][0]=euler[i];
for(j=1;j<LOG;++j)
for(i=1;i<2*n;++i){
rmq[i][j]=rmq[i][j-1];
int urm=i+(1<<(j-1));
if(urm<2*n){
int rmq1=rmq[i][j];
int rmq2=rmq[urm][j-1];
if(h[rmq1]>h[rmq2])
rmq[i][j]=rmq2;
}
}
for(i=2;i<MAX;++i)
logar[i]=logar[i/2]+1;
}
int get_lca(int nod1,int nod2){
int pos1=pos[nod1];
int pos2=pos[nod2];
if(pos1>pos2)
swap(pos1,pos2);
int len=pos2-pos1+1;
int loga=logar[len];
int rmq1=rmq[pos1][loga];
int rmq2=rmq[pos2-(1<<loga)+1][loga];
if(h[rmq1]<h[rmq2])
return rmq1;
else
return rmq2;
}
void add_path(int nod,int anc){
++used[nod];
--used[anc];
}
bool cmp(int nod1,int nod2){
return pos[nod1]<pos[nod2];
}
void process_queries(){
int i;
for(i=1;i<=m;++i){
int sz;
cin>>sz;
int j;
for(j=1;j<=sz;++j)
cin>>query[j];
sort(query+1,query+sz+1,cmp);
for(j=2;j<=sz;++j)
add_path(query[j],get_lca(query[j],query[j-1]));
add_path(query[1],get_lca(query[1],query[sz]));
}
}
int dfs_path(int nod,int tata){
for(auto fiu : tree[nod])
if(fiu!=tata)
used[nod]+=dfs_path(fiu,nod);
return used[nod];
}
void get_answer(){
vector<int>ans;
int i;
for(i=1;i<n;++i){
auto [nod,par]=edg[i];
if(h[nod]<h[par])
swap(nod,par);
if(used[nod]>=k)
ans.push_back(i);
}
cout<<ans.size()<<'\n';
for(auto elem : ans)
cout<<elem<<' ';
}
int main()
{
read();
dfs(1,0);
get_rmq();
process_queries();
dfs_path(1,0);
get_answer();
return 0;
}
