#include <bits/stdc++.h>
#define DEBUG 0
using namespace std;
const int MAX_N = 1e5 + 10;
int timer, k;
vector <pair <int, int>> graph[MAX_N];
int depth[MAX_N], parent[MAX_N][20];
int st[MAX_N], pos[MAX_N], edge[MAX_N];
int qs[MAX_N];
vector <int> ans;
void dfs(const int &u, const int &p) {
timer++;
st[u] = timer;
pos[timer] = u;
for(int i = 1; i < 20; i++) {
parent[u][i] = parent[parent[u][i - 1]][i - 1];
}
for(auto [v, i] : graph[u]) {
if(v == p) {
continue;
}
edge[v] = i;
depth[v] = depth[u] + 1;
parent[v][0] = u;
dfs(v, u);
}
}
int find_lca(const int &a, const int &b) {
int u = a, v = b;
if(depth[u] < depth[v]) {
swap(u, v);
}
for(int i = 19; i >= 0; i--) {
if(depth[parent[u][i]] >= depth[v]) {
u = parent[u][i];
}
}
for(int i = 19; i >= 0; i--) {
if(parent[u][i] != parent[v][i]) {
u = parent[u][i];
v = parent[v][i];
}
}
return (u == v ? u : parent[u][0]);
}
int dfs2(const int &u, const int &p) {
int sum = qs[u];
for(auto [v, i] : graph[u]) {
if(v != p) {
sum += dfs2(v, u);
}
}
if(sum >= k) {
ans.push_back(edge[u]);
}
return sum;
}
int main() {
cin.tie(0)->sync_with_stdio(0);
int n, m;
cin >> n >> m >> k;
for(int i = 1; i <= n - 1; i++) {
int a, b;
cin >> a >> b;
graph[a].emplace_back(b, i);
graph[b].emplace_back(a, i);
}
depth[0] = -1;
dfs(1, -1);
while(m--) {
int s;
cin >> s;
vector <int> vec;
while(s--) {
int x;
cin >> x;
vec.push_back(x);
}
sort(vec.begin(), vec.end(), [&](const int &a, const int &b) {
return st[a] < st[b];
});
stack <int> latest_lca;
stack <int> node;
node.push(vec[0]);
for(int i = 1; i < vec.size(); i++) {
while(!latest_lca.empty() and st[latest_lca.top()] >= st[find_lca(vec[i], node.top())]) {
qs[node.top()]++;
node.pop();
qs[node.top()]++;
node.pop();
qs[latest_lca.top()] -= 2;
node.push(latest_lca.top());
latest_lca.pop();
}
latest_lca.push(find_lca(vec[i], node.top()));
node.push(vec[i]);
}
while(!latest_lca.empty()) {
qs[node.top()]++;
node.pop();
qs[node.top()]++;
node.pop();
qs[latest_lca.top()] -= 2;
node.push(latest_lca.top());
latest_lca.pop();
}
}
dfs2(1, -1);
cout << ans.size() << '\n';
sort(ans.begin(), ans.end());
for(auto v : ans) {
cout << v << ' ';
}
return 0;
}
