#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pll pair<int, int>
#define mp make_pair
#define pb push_back
#define f first
#define s second
int n,m,k;
vector<int> num(100005), ans(100005, 0);
vector<map<int,int>> v(100005);
vector<vector<pair<int,int>>> al(100005);
vector<vector<int>> here(100005);
vector<int> abv;
void dfs(int x, int pind){
for(int it:here[x]){
v[x][it]++;
ans[x]++;
}
for(auto [to, ind] : al[x]){
if(ind==pind)continue;
dfs(to, ind);
// merge into v[x]
if(v[to].size() > v[x].size())swap(v[to], v[x]);
ans[x]+=ans[to];
for(auto [dep, amt] : v[to]){
v[x][dep]+=amt;
if(v[x][dep]>amt){
ans[x]--;
}
if(v[x][dep]==num[dep]){
ans[x]--;
}
}
}
if(ans[x] >= k){
abv.pb(pind);
}
//~ printf("at %lld, ans is %lld\n", x, ans[x]);
//~ for(auto [dep, amt]:v[x]){
//~ printf("(%lld, %lld) ",dep, amt);
//~ }
//~ cout<<endl;
}
signed main(){
cin>>n>>m>>k;
for(int i=1;i<=n-1;i++){
int a,b;cin>>a>>b;
al[a].pb({b,i});
al[b].pb({a,i});
}
for(int i=0;i<m;i++){
int si;cin>>si;
for(int j=0;j<si;j++){
int ep;cin>>ep;
here[ep].pb(i);
}
num[i]=si;
}
dfs(1, -1);
cout<<abv.size()<<"\n";
sort(abv.begin(),abv.end());
for(auto it:abv){
cout<<it<<" ";
}
}
