#include <bits/stdc++.h>
using namespace std;
const int N = 1e5;
int n, m, k, dep[N], cnt[N], curr[N], ans[N];
pair<int, int> p[N];
vector<int> a[N];
vector<pair<int, int>> adj[N];
set<int> st[N];
void dfs(int x, int par, int preIdx) {
p[x] = make_pair(par, preIdx);
a[dep[x]].push_back(x);
for (auto &[y, idx] : adj[x]) {
if (y == par) continue;
dep[y] = dep[x]+1;
dfs(y, x, idx);
}
}
signed main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
memset(curr, 0, sizeof(curr));
memset(ans, 0, sizeof(ans));
cin >> n >> m >> k;
for (int i = 0; i < n-1; i++) {
int x, y;
cin >> x >> y;
x--; y--;
adj[x].push_back(make_pair(y, i));
adj[y].push_back(make_pair(x, i));
}
for (int i = 0; i < m; i++) {
int x; cin >> x;
cnt[i] = x;
for (int j = 0; j < x; j++) {
int y; cin >> y; y--;
st[y].insert(i);
}
}
dep[0] = 0;
dfs(0, 0, 0);
for (int i = n-1; i > 0; i--) {
for (int &x : a[i]) {
// sumar sz a la arista hacia mi padre
int sz = st[x].size();
ans[p[x].second] += sz;
int pp = p[x].first;
if (st[x].size() > st[pp].size()) st[x].swap(st[pp]);
while (!st[x].empty()) {
int y = *st[x].begin();
st[x].erase(st[x].begin());
auto it = st[pp].find(y);
if (it != st[pp].end()) {
if (++curr[y] + 1 == cnt[y]) st[pp].erase(it);
}
else {
st[pp].insert(y);
}
}
}
}
vector<int> edges;
for (int i = 0; i < n-1; i++) {
if (ans[i] >= k) {
edges.push_back(i);
}
}
cout << edges.size() << "\n";
for (int& i : edges) {
cout << i+1 << " ";
}
cout << "\n";
}
