#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
const int N = 1e5 + 5, LG = 17;
int n, m, k;
int L[N], R[N], pr[LG][N], dep[N], par[N], cnt[N], sz[N], ind[N];
bool spec[N];
vector<array<int, 2>> g[N];
int timer;
void dfs(int u) {
L[u] = ++timer;
for (auto [v, id] : g[u]) {
if (!L[v]) {
ind[v] = id;
dep[v] = dep[u] + 1;
pr[0][v] = u;
for (int i = 1; i < LG; ++i) {
pr[i][v] = pr[i - 1][pr[i - 1][v]];
}
dfs(v);
}
}
R[u] = timer;
}
int lca(int u, int v) {
if (dep[u] < dep[v]) {
swap(u, v);
}
for (int i = LG - 1; ~i; --i) {
if (dep[u] - (1 << i) >= dep[v]) {
u = pr[i][u];
}
}
if (u == v) {
return u;
}
for (int i = LG - 1; ~i; --i) {
if (pr[i][u] ^ pr[i][v]) {
u = pr[i][u];
v = pr[i][v];
}
}
return pr[0][u];
}
bool cmp(int u, int v) {
return L[u] < L[v];
}
int main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
cin >> n >> m >> k;
for (int i = 1; i < n; ++i) {
int u, v; cin >> u >> v;
g[u].push_back({v, i});
g[v].push_back({u, i});
}
dfs(1);
while (m--) {
int s; cin >> s;
vector<int> cnd(s);
for (int &x : cnd) {
cin >> x;
++cnt[x];
spec[x] = 1;
}
sort(cnd.begin(), cnd.end(), cmp);
for (int i = 1; i < s; ++i) {
cnd.push_back(lca(cnd[i], cnd[i - 1]));
}
sort(cnd.begin(), cnd.end(), cmp);
cnd.erase(unique(cnd.begin(), cnd.end()), cnd.end());
vector<int> st;
for (int u : cnd) {
while (st.size() && R[st.back()] < L[u]) {
st.pop_back();
}
par[u] = st.size() ? st.back() : 0;
sz[u] = 0;
st.push_back(u);
}
for (int i = cnd.size() - 1; ~i; --i) {
int u = cnd[i];
sz[u] += spec[u];
if (!par[u]) {
cnt[u] -= sz[u];
} else {
cnt[u] -= sz[u] - 1;
++sz[par[u]];
}
}
for (int u : cnd) {
spec[u] = 0;
}
}
vector<int> ord(n); iota(ord.begin(), ord.end(), 1);
sort(ord.rbegin(), ord.rend(), cmp);
vector<int> res;
for (int u : ord) {
if (cnt[u] >= k) {
res.push_back(ind[u]);
}
cnt[pr[0][u]] += cnt[u];
}
cout << res.size() << "\n";
sort(res.begin(), res.end());
for (int x : res) {
cout << x << " ";
}
return 0;
}
