#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
int n, m, k;
vector<pair<int, int>> graph[100001];
int tin[100001], tout[100001], timer = 0, anc[100001][20], p_edge[100001];
int chosen[50001];
int bit1[100001], bit2[100001];
void dfs(int node = 1, int parent = 0) {
tin[node] = ++timer;
for (int i = 1; i < 20; i++) anc[node][i] = anc[anc[node][i - 1]][i - 1];
for (pair<int, int> i : graph[node]) if (i.first != parent) {
anc[i.first][0] = node;
p_edge[i.first] = i.second;
dfs(i.first, node);
}
tout[node] = timer;
}
bool is_ancestor(int a, int b) {
return (tin[a] <= tin[b] && tout[a] >= tout[b]);
}
int lca(int a, int b) {
if (is_ancestor(a, b)) return a;
for (int i = 19; ~i; i--) {
if (anc[a][i] && !is_ancestor(anc[a][i], b)) a = anc[a][i];
}
return anc[a][0];
}
void update(int bit[100001], int pos, int val) {
for (; pos <= n; pos += pos & (-pos)) bit[pos] += val;
}
int query(int bit[100001], int a, int b) {
int ans = 0;
for (; b; b -= b & (-b)) ans += bit[b];
for (a--; a; a -= a & (-a)) ans -= bit[a];
return ans;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m >> k;
for (int i = 1; i < n; i++) {
int a, b;
cin >> a >> b;
graph[a].push_back({b, i});
graph[b].push_back({a, i});
}
dfs();
while (m--) {
int s, l;
cin >> s;
for (int i = 0; i < s; i++) {
cin >> chosen[i];
if (!i) l = chosen[i];
else l = lca(l, chosen[i]);
}
for (int i = 0; i < s; i++) {
int curr = chosen[i];
if (curr == l) continue;
for (int j = 19; ~j; j--) {
int nxt = anc[curr][j];
if (nxt && !is_ancestor(nxt, l) && !query(bit2, tin[nxt], tout[nxt])) {
update(bit1, tin[curr], 1);
update(bit2, tin[curr], 1);
update(bit1, tin[nxt], -1);
update(bit2, tin[nxt], -1);
curr = nxt;
}
}
update(bit1, tin[curr], 1);
update(bit2, tin[curr], 1);
update(bit1, tin[anc[curr][0]], -1);
update(bit2, tin[anc[curr][0]], -1);
}
for (int i = 0; i < s; i++) {
int curr = chosen[i];
if (curr == l) continue;
for (int j = 19; ~j; j--) {
int nxt = anc[curr][j];
if (nxt && !is_ancestor(nxt, l) && query(bit2, tin[nxt], tout[nxt])) {
update(bit2, tin[curr], -1);
update(bit2, tin[nxt], 1);
curr = nxt;
}
}
update(bit2, tin[curr], -1);
update(bit2, tin[anc[curr][0]], 1);
}
}
vector<int> ans;
for (int i = 2; i <= n; i++) if (query(bit1, tin[i], tout[i]) >= k) {
ans.push_back(p_edge[i]);
}
sort(ans.begin(), ans.end());
cout << ans.size() << '\n';
for (int i : ans) cout << i << ' ';
return 0;
}
