#define taskname ""
#include <bits/stdc++.h>
using namespace std;
const int kN = 1e5 + 1;
const int kLG = 20;
int n, m, k, timer, in[kN], out[kN], jump[kLG][kN];
vector<int> adj[kN];
vector<pair<int, int>> edges;
void DFS(int u, int p) {
in[u] = ++timer;
jump[0][u] = p;
for (int i = 1; i < kLG; i++) {
jump[i][u] = jump[i - 1][jump[i - 1][u]];
}
for (auto v : adj[u]) {
if (v == p) {
continue;
}
DFS(v, u);
}
out[u] = timer;
}
bool Ancestor(int u, int v) {
return (in[u] <= in[v] && out[v] <= out[u]);
}
int LCA(int u, int v) {
if (Ancestor(u, v)) {
return u;
}
for (int i = kLG - 1; i >= 0; i--) {
if (jump[i][u] >= 1 && !Ancestor(jump[i][u], v)) {
u = jump[i][u];
}
}
return jump[0][u];
}
struct FenwickTree {
int t;
vector<int> bit;
FenwickTree(int _t) : t(_t) {
bit.resize(t + 1, 0);
}
void Update(int p, int x) {
for (int i = p; i <= t; i += i & (-i)) {
bit[i] += x;
}
}
int PrefixSum(int p) {
int k = 0;
for (int i = p; i > 0; i -= i & (-i)) {
k += bit[i];
}
return k;
}
int RangeSum(int l, int r) {
return PrefixSum(r) - PrefixSum(l - 1);
}
};
int main() {
if (fopen(taskname".inp", "r")) {
freopen(taskname".inp", "r", stdin);
freopen(taskname".out", "w", stdout);
}
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> m >> k;
for (int i = 1; i < n; i++) {
int a, b;
cin >> a >> b;
edges.push_back({a, b});
adj[a].push_back(b);
adj[b].push_back(a);
}
int root = 1;
DFS(root, 0);
FenwickTree a(n);
for (int i = 1; i <= m; i++) {
int s;
cin >> s;
vector<int> b;
for (int j = 1; j <= s; j++) {
int c;
cin >> c;
b.push_back(c);
}
sort(b.begin(), b.end(), [&](int x, int y) {
return in[x] < in[y];
});
b.push_back(b[0]);
for (int j = 0; j + 1 < b.size(); j++) {
a.Update(in[b[j]], 1);
a.Update(in[b[j + 1]], 1);
a.Update(in[LCA(b[j], b[j + 1])], -2);
}
}
vector<int> result;
for (int i = 0; i < n - 1; i++) {
if (jump[0][edges[i].first] == edges[i].second) {
swap(edges[i].first, edges[i].second);
}
if (a.RangeSum(in[edges[i].second], out[edges[i].second]) >= 2 * k) {
result.push_back(i + 1);
}
}
cout << result.size() << '\n';
for (int i : result) {
cout << i << ' ';
}
return 0;
}
