#include "bits/stdc++.h"
using namespace std;
void abc() {cout << endl;}
template <typename T, typename ...U> void abc(T a, U ...b) {
cout << a << ' ', abc(b...);
}
template <typename T> void printv(T l, T r) {
while (l != r) cout << *l << " \n"[++l == r];
}
template <typename A, typename B> istream& operator >> (istream& o, pair<A, B> &a) {
return o >> a.first >> a.second;
}
template <typename A, typename B> ostream& operator << (ostream& o, pair<A, B> a) {
return o << '(' << a.first << ", " << a.second << ')';
}
template <typename T> ostream& operator << (ostream& o, vector<T> a) {
bool is = false;
for (T i : a) {o << (is ? ' ' : '{'), is = true, o << i;}
return o << '}';
}
#ifdef local
#define test(args...) abc("[" + string(#args) + "]", args)
#else
#define test(args...) void(0)
#endif
using ll = long long;
vector<int> adj[100005];
vector<int> person[50005];
int st[100005];
int timer = 1;
int h[100005];
int jmp[100005][20];
void dfs(int node, int par = -1) {
st[node] = timer++;
for (int j = 1; j < 20; j++) {
jmp[node][j] = jmp[jmp[node][j-1]][j-1];
}
for (auto nxt : adj[node]) {
if (nxt == par) continue;
h[nxt] = h[node] + 1;
jmp[nxt][0] = node;
dfs(nxt, node);
}
}
int lca(int a, int b) {
if (h[a] > h[b]) swap(a, b);
for (int j = 19; j >= 0; j--) {
if (h[jmp[b][j]] >= h[a]) b = jmp[b][j];
}
if (a == b) return a;
for (int j = 19; j >= 0; j--) {
if (jmp[a][j] != jmp[b][j]) {
a = jmp[a][j]; b = jmp[b][j];
}
}
return jmp[a][0];
}
int node[100005];
int val[100005];
int dfs2(int cur, int par) {
val[cur] = node[cur];
for (auto nxt : adj[cur]) {
if (nxt == par) continue;
val[cur] += dfs2(nxt, cur);
}
return val[cur];
}
vector<pair<int, int>> edges;
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
// freopen("", "r", stdin);
// freopen("", "w", stdout);
int n, m, k; cin >> n >> m >> k;
for (int i = 0; i < n - 1; i++) {
int a, b; cin >> a >> b; adj[a].push_back(b); adj[b].push_back(a); edges.emplace_back(a, b);
}
h[1] = 1;
jmp[1][0] = 1;
dfs(1);
for (int i = 0; i < m; i++) {
int s ;cin >> s;
vector<int> temp;
for (int j = 0; j < s; j++) {
int t; cin >> t; temp.push_back(t);
}
sort(temp.begin(), temp.end(), [](int a, int b) {
return st[a] < st[b];
});
for (int j = 0; j < s; j++) {
int a = temp[j], b = temp[(j + 1) % s];
int l = lca(a, b);
node[a]++; node[b]++; node[l] -= 2;
}
}
vector<int> ans;
dfs2(1, -1);
int i = 1;
for (auto edge :edges) {
int a = (h[edge.first] > h[edge.second] ? edge.first : edge.second);
if (val[a] >= 2 * k) ans.push_back(i);
i++;
}
cout << ans.size() << endl;
for (auto a : ans) cout << a << " ";
}
