#include <bits/stdc++.h>
using namespace std;
#define int long long
#define speedIO ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define mod 1000000007
#define f first
#define s second
#define pii pair<int,int>
#define pb push_back
vector<vector<int>> graph,up;
vector<int> tin,depth,ans,cnt;
int tyme;
void dfs(int u, int p){
tyme++;
tin[u]=tyme;
up[u][0]=p;
depth[u]=depth[p]+1;
for(int i=1;i<21;i++){
up[u][i]=up[up[u][i-1]][i-1];
}
for(int v:graph[u]){
if(v==p) continue;
dfs(v,u);
}
}
int lca(int u, int v){
if(depth[u]>depth[v]){
swap(u,v);
}
int d=depth[v]-depth[u];
for(int i=20;i>=0;i--){
if(d&(1<<i)){
v=up[v][i];
}
}
if(u==v){
return u;
}
for(int i=20;i>=0;i--){
if(up[u][i]!=up[v][i]){
u=up[u][i];
v=up[v][i];
}
}
return up[u][0];
}
void dfs2(int u, int p){
ans[u]+=cnt[u];
for(int v:graph[u]){
if(v==p){
continue;
}
dfs2(v,u);
ans[u]+=ans[v];
}
}
int32_t main(){
speedIO;
int t,n,m,k,q;
//cin>>t;
t=1;
while(t--){
cin>>n>>m>>k;
graph.clear();
graph.resize(n+1);
tin.clear();
tin.resize(n+1);
up.clear();
up.resize(n+1, vector<int>(21));
depth.clear();
depth.resize(n+1,0);
vector<pii> edges(n-1);
cnt.clear();
cnt.resize(n+1,0);
ans.clear();
ans.resize(n+1,0);
for(int i=0;i<n-1;i++){
int u,v;
cin>>u>>v;
graph[u].pb(v);
graph[v].pb(u);
edges[i]={u,v};
}
tyme=0;
tin[0]=0;
dfs(1,0);
vector<int> eees(n+1);
for(int i=0;i<n-1;i++){
int u=edges[i].f,v=edges[i].s;
if(u==up[v][0]){
eees[v]=i+1;
}else{
eees[u]=i+1;
}
}
while(m--){
int x;
cin>>x;
vector<pii> a(x);
for(int i=0;i<x;i++){
cin>>a[i].s;
a[i].f=tin[a[i].s];
cnt[a[i].s]++;
}
sort(a.begin(),a.end());
for(int i=0;i<x;i++){
int u=lca(a[i].s,a[(i+1)%x].s);
//cout<<a[i].s<<' '<<u<<'\n';
cnt[u]--;
}
}
dfs2(1,0);
vector<int> blah;
for(int i=1;i<=n;i++){
if(ans[i]>=k){
blah.pb(eees[i]);
}
}
cout<<blah.size()<<'\n';
sort(blah.begin(),blah.end());
for(int i:blah){
cout<<i<<' ';
}
}
return 0;
}
