#include <bits/stdc++.h>
using namespace std;
vector<int>adj[200005];
int ind[200005], tim[200005];
int dep[200005];
int a[200005]; //actual rmq array (corresponding depths of tour vector)
vector<int>tour;
int timer=0;
void dfs(int i,int p){
tim[i]=timer++;
if(!dep[i]) dep[i]=dep[p]+1;
ind[i]=tour.size();
tour.push_back(i);
for(int j:adj[i]){
if(j!=p){
dfs(j,i);
tour.push_back(i);
}
}
}
int st[200005][20];
void build(int n){
for(int i=0;i<n;i++){
st[i][0]=i;
}
for(int j=1;(1<<j)<=n;j++){
for(int i=0;i+(1<<j)<=n;i++){
if(a[st[i][j-1]]>a[st[i+(1<<(j-1))][j-1]]){
st[i][j]=st[i+(1<<(j-1))][j-1];
}
else{
st[i][j]=st[i][j-1];
}
}
}
}
int query(int l,int r){
int j=(int)log2(r-l+1);
if(a[st[l][j]]<a[st[r-(1<<j)+1][j]]){
return st[l][j];
}
return st[r-(1<<j)+1][j];
}
int lca(int x,int y){
if(ind[x]>ind[y]) swap(x,y);
return tour[query(ind[x],ind[y])];
}
bool cmp(int x, int y){
return tim[x]<tim[y];
}
int cnt[200005];
void go(int x, int p){
for(int y:adj[x]){
if(y==p) continue;
go(y, x);
cnt[x]+=cnt[y];
}
}
vector<pair<int, int>>edges;
int main(){
int n, m, k;
cin>>n>>m>>k;
for(int i=1;i<n;i++){
int x, y;
cin>>x>>y;
adj[x].push_back(y);
adj[y].push_back(x);
edges.push_back({x, y});
}
dfs(1, 0);
for(int i=0;i<tour.size();i++){
a[i]=dep[tour[i]];
}
build(tour.size());
for(int i=1;i<=m;i++){
int s;
cin>>s;
vector<int>v;
for(int j=0;j<s;j++){
int x;
cin>>x;
v.push_back(x);
}
sort(v.begin(), v.end(), cmp);
for(int i=0;i<s;i++){
int u=v[i], t=v[(i+1)%s];
//cout<<u<<" "<<t<<" "<<lca(u, t)<<endl;
cnt[u]++;
cnt[t]++;
cnt[lca(u, t)]-=2;
}
//cout<<endl;
}
go(1, 0);
vector<int>ans;
for(int i=0;i<n-1;i++){
int x=edges[i].first, y=edges[i].second;
if(dep[x]<dep[y]) swap(x, y);
//cout<<x<<" "<<y<<" "<<cnt[x]<<endl;
if(cnt[x]>=2*k) ans.push_back(i+1);
}
cout<<ans.size()<<"\n";
for(int i:ans) cout<<i<<" ";
}
