#include <bits/stdc++.h>
using namespace std;
int n,m,k,u,v,tin,diff[100005],s[100005];
int in[100005],out[100005],lift[25][100005];
vector<pair<int,int> > grh[100005];
bool is(int x,int y){
return in[x]<=in[y] && out[x]>=out[y];
}
int lca(int x,int y){
if (is(x,y)) return x;
if (is(y,x)) return y;
for (int i=20;i>=0;i--){
if (lift[i][x] && !is(lift[i][x],y)){
x=lift[i][x];
}
}
return lift[0][x];
}
void euler(int x,int p){
in[x]=++tin; lift[0][x]=p;
for (int i=1;i<=20;i++) {
lift[i][x]=lift[i-1][lift[i-1][x]];
}
for (auto i:grh[x]) {
if (i.first!=p) euler(i.first,x);
}
out[x]=++tin;
}
bool cp(int x,int y){
return in[x]<in[y];
}
vector<int> ans;
void dfs(int x,int p){
for (auto i:grh[x]){
if (i.first!=p){
dfs(i.first,x);
diff[x]+=diff[i.first];
if (diff[i.first]>=k) ans.push_back(i.second);
}
}
}
int main(){
cin>>n>>m>>k;
for (int i=1;i<n;i++){
cin>>u>>v;
grh[u].push_back({v,i});
grh[v].push_back({u,i});
}
euler(1,0);
in[n+1]=out[n+1]=INT_MAX;
while (m--){
int k; cin>>k;
int anc=0;
for (int i=1;i<=k;i++) {
cin>>s[i];
if (i==1) anc=s[i];
else anc=lca(anc,s[i]);
}
s[k+1]=n+1;
sort(s+1,s+1+k,cp);
vector<int> imp,vt; set<pair<int,int> > implca;
for (int i=1;i<=k;i++){
if (out[s[i]]<in[s[i+1]]) {
imp.push_back(s[i]);
implca.insert({in[s[i]],s[i]});
diff[s[i]]++;
}
}
for (int i=1;i<imp.size();i++){
int nde=lca(imp[i-1],imp[i]);
if (nde!=anc) {
implca.insert({in[nde],nde});
}
}
for (auto it=implca.begin();it!=implca.end();it++) vt.push_back(it->second);
sort(vt.begin(),vt.end(),cp); vt.push_back(n+1);
for (int i=vt.size()-2;i>=0;i--){
auto lt=implca.lower_bound({in[vt[i]]+1,-1});
auto rt=implca.upper_bound({out[vt[i]],-1});
vector<set<pair<int,int>>::iterator> tr;
for (auto it=lt;it!=implca.end();it++){
if (is(vt[i],it->second)) tr.push_back(it);
}
if (tr.empty()) continue;
diff[vt[i]]=diff[vt[i]]-(int)tr.size()+1;
//cout<<vt[i]<<" "<<tr.size()<<"\n";
for (auto it:tr) implca.erase(it);
}
int cnt=implca.size();
// cout<<cnt<<"\n";
diff[anc]-=cnt;
}
dfs(1,0);
// for (int i=1;i<=n;i++) cout<<diff[i]<<" ";cout<<"\n";
sort(ans.begin(),ans.end());
cout<<ans.size()<<"\n";
if (ans.empty()) return 0;
cout<<ans[0];
for (int i=1;i<ans.size();i++) cout<<" "<<ans[i];
cout<<"\n";
}
/*
13 1 1
1 2
2 3
3 4
3 5
3 6
6 7
7 8
7 9
6 10
3 11
11 12
11 13
8 2 4 5 8 9 10 12 13
*/
