#include "bits/stdc++.h"
using namespace std;
vector <vector <int>> g;
map <pair <int,int>,int> mp, edge, path;
int f;
void dfs(int v, const int target, int p = -1) {
if(p != -1) path[{min(v, p), max(v, p)}] ++;
if(v == target) {
f = 1;
return;
}
for(auto u : g[v]) {
if(u == p) continue;
dfs(u, target, v);
if(f) return;
}
if(p != -1 && !f)
path[{min(v, p), max(v, p)}] --;
}
signed main () {
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n, m, k;
cin >> n >> m >> k;
g.resize(n);
for(int i = 0; i < n - 1; i ++) {
int u, v;
cin >> u >> v;
u --, v --;
edge[{min(u, v), max(u, v)}] = i + 1;
g[u].push_back(v);
g[v].push_back(u);
}
for(int i = 0; i < m; i ++) {
int sz;
cin >> sz;
int prev;
cin >> prev;
prev --;
for(int j = 0; j < sz - 1; j ++) {
int v;
cin >> v;
v --;
f = 0;
dfs(v, prev);
prev = v;
}
for(auto &j : path) mp[j.first] += (j.second > 0), j.second = 0;
}
vector <pair <int,int>> proof;
for(auto i : mp) {
if(i.second >= k) proof.push_back(i.first);
}
cout << proof.size() << "\n";
for(auto i : proof) {
cout << edge[i] << " ";
}
return 0;
}
