#include <bits/stdc++.h>
using namespace std;
const int M = 100001;
int n,m,k,ile[M]; vector<int> odp;
vector<pair<int,int>> tree[M];
map<int,int> mp[M];
void dfs(int v, int p, int ind) {
for (auto [u,i] : tree[v]) {
if (u == p)
continue;
dfs(u,v,i);
if (mp[v].size() < mp[u].size())
swap(mp[v],mp[u]);
for (auto it = mp[u].begin(); it != mp[u].end(); it++) {
mp[v][it->first] += it->second;
if (mp[v][it->first] == ile[it->first])
mp[v].erase(it->first);
}
mp[u].clear();
}
if (mp[v].size() >= k)
odp.push_back(ind);
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> n >> m >> k; int a,b;
for (int i = 1; i < n; i++)
cin >> a >> b, tree[a].push_back({b,i}), tree[b].push_back({a,i});
for (int i = 0; i < m; i++) {
cin >> ile[i];
for (int j = 0; j < ile[i]; j++)
cin >> a, mp[a][i] = 1;
}
dfs(1,0,0), sort(odp.begin(),odp.end());
cout << odp.size() << endl;
for (int i : odp)
cout << i << " ";
cout << endl;
return 0;
}
