#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define dbg(...) 47
#endif
constexpr int N = 1e5;
vector<int> g[N];
int lvl[N], par[N], t[N];
void dfs_lvl(int u) {
for (auto v : g[u]) {
if (v != par[u]) {
par[v] = u;
lvl[v] = lvl[u] + 1;
dfs_lvl(v);
}
}
}
void update(int u, int v) {
if (lvl[u] > lvl[v]) swap(u, v);
t[v]++;
if (par[u] != -1) {
t[par[u]]--;
}
}
void dfs(int u) {
for (auto v : g[u]) {
if (v != par[u]) {
dfs(v);
t[u] += t[v];
}
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m, k;
cin >> n >> m >> k;
vector<int> u(n - 1), v(n - 1);
for (int i = 0; i < n - 1; i++) {
cin >> u[i] >> v[i];
u[i]--; v[i]--;
g[u[i]].push_back(v[i]);
g[v[i]].push_back(u[i]);
}
par[0] = -1;
dfs_lvl(0);
for (int i = 0; i < m; i++) {
int s;
cin >> s;
vector<int> a(s);
for (int j = 0; j < s; j++) {
cin >> a[j];
a[j]--;
}
ranges::sort(a, [&](int x, int y) {
return lvl[x] < lvl[y];
});
for (int pos = 1; pos < s; pos++) {
update(a[pos - 1], a[pos]);
}
}
dfs(0);
vector<int> ans;
for (int i = 0; i < n - 1; i++) {
if (t[u[i]] >= k && t[v[i]] >= k) {
ans.push_back(i + 1);
}
}
cout << ans.size() << '\n';
for (auto i : ans) {
cout << i << ' ';
}
cout << '\n';
return 0;
}
