#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
int n, m, k;
vector<pair<int, int>> a[100001];
pair<int, int> e[100001];
int dem[100001];
vector<int> luu[100001];
unordered_map<int, int> mp[100001];
vector<int> res;
void dfs(int u, int p){
for (auto [v, id]:a[u]){
if(v!=p){
dfs(v, u);
if(mp[v].size()>=k){
res.push_back(id);
}
if(mp[u].size() < mp[v].size())swap(mp[u], mp[v]);
for (auto i:mp[v]){
mp[u][i.f]+=i.s;
if(mp[u][i.f]==dem[i.f])mp[u].erase(i.f);
}
}
}
for (int i:luu[u]){
mp[u][i]++;
if(mp[u][i]==dem[i])mp[u].erase(i);
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m >> k;
for (int i= 1;i<n;++i){
int u, v;
cin >> u >> v;
a[u].push_back({v, i});
a[v].push_back({u, i});
}
for (int i = 1;i<=m;++i){
int s;
cin >> s;
dem[i] = s;
for (int j = 1;j<=s;++j){
int u;
cin >> u;
luu[u].push_back(i);
}
}
dfs(1, 0);
sort(res.begin(), res.end());
cout << res.size() << '\n';
for (int i:res){
cout << i << ' ';
}
}
