#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define dbg(...) 47
#endif
constexpr int N = 1e5;
constexpr int LOG = 20;
vector<int> g[N];
int lvl[N], par[N][LOG], t[N];
void dfs_lvl(int u, int p) {
par[u][0] = p;
for (int i = 1; i < LOG; i++) {
if (par[u][i - 1] == -1) par[u][i] = -1;
else par[u][i] = par[par[u][i - 1]][i - 1];
}
for (auto v : g[u]) {
if (v == p) continue;
lvl[v] = lvl[u] + 1;
dfs_lvl(v, u);
}
}
int lca(int u, int v) {
if (lvl[u] < lvl[v]) swap(u, v);
int diff = lvl[u] - lvl[v];
for (int i = 0; i < LOG; i++) {
if (diff & (1 << i)) {
u = par[u][i];
}
}
if (u == v) return u;
for (int i = LOG - 1; i >= 0; i--) {
if (par[u][i] != par[v][i]) {
u = par[u][i];
v = par[v][i];
}
}
return par[u][0];
}
void update(int u, int v, int d) {
int l = lca(u, v);
t[u] += d;
t[v] += d;
t[l] -= 2 * d;
}
void dfs(int u, int p) {
for (auto v : g[u]) {
if (v == p) continue;
dfs(v, u);
t[u] += t[v];
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m, k;
cin >> n >> m >> k;
vector<int> u(n - 1), v(n - 1);
map<pair<int, int>, int> pos;
for (int i = 0; i < n - 1; i++) {
cin >> u[i] >> v[i];
u[i]--; v[i]--;
pos[{u[i], v[i]}] = i;
pos[{v[i], u[i]}] = i;
g[u[i]].push_back(v[i]);
g[v[i]].push_back(u[i]);
}
for (int i = 0; i < N; i++) {
for (int j = 0; j < LOG; j++) {
par[i][j] = -1;
}
}
dfs_lvl(0, -1);
for (int i = 0; i < m; i++) {
int s;
cin >> s;
vector<int> a(s);
for (int j = 0; j < s; j++) {
cin >> a[j];
a[j]--;
}
ranges::sort(a, [&](int x, int y) {
return lvl[x] < lvl[y];
});
for (int j = 1; j < s; j++) {
update(a[j - 1], a[j], 1);
if (j < s - 1) {
update(a[j], lca(a[j], a[j + 1]), -1);
}
}
}
dfs(0, -1);
vector<int> ans;
for (int i = 1; i < n; i++) {
if (t[i] >= k) {
int j = par[i][0];
ans.push_back(pos[{i, j}] + 1);
}
}
cout << ans.size() << '\n';
for (auto i : ans) {
cout << i << ' ';
}
cout << '\n';
return 0;
}
