#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
using namespace std;
const int MAXN = 1e5 + 123;
vector<int> edg[MAXN];
vector<int> redg[MAXN];
int rtnum[MAXN];
int depth[MAXN];
int timer = 0;
int tin[MAXN];
int tout[MAXN];
int to_root_add[MAXN];
pair<int, int> ghash(int v, int u) {
if (v > u)
return {u, v};
return {v, u};
}
void dfsinit(int v, map<pair<int, int>, int>& mp) {
tin[v] = timer++;
if (redg[v].size()) {
for (int j = 0;; ++j) {
int u = redg[v][j];
if (j >= redg[u].size())
break;
redg[v].push_back(redg[u][j]);
}
}
for (auto u : edg[v]) {
if (redg[v].size() && u == redg[v][0])
continue;
rtnum[u] = mp[ghash(v, u)];
redg[u].push_back(v);
depth[u] = depth[v] + 1;
dfsinit(u, mp);
}
tout[v] = timer;
}
int lca(int u, int v) {
if (depth[u] > depth[v]) {
int t = depth[u] - depth[v];
for (int j = redg[u].size(); j >= 0; --j) {
if (t & (1 << j)) {
u = redg[u][j];
t -= (1 << j);
}
}
}
if (depth[v] > depth[u])
return lca(v, u);
if (u == v)
return v;
//cout << "MYUKU" << ' ' << u << ' ' << v << ": " << depth[u] << ' ' << depth[v] << endl;
for (int j = redg[u].size() - 1; j >= 0; --j) {
if (j < redg[u].size() && redg[u][j] != redg[v][j]) {
u = redg[u][j];
v = redg[v][j];
}
}
//cout << "UNYU~" << endl;
return redg[u][0];
}
bool cmptin(int i, int j) {
return tin[i] < tin[j];
}
int get_ans_dfs(int v, int k, vector<int>& ans) {
int cnt = 0;
for (auto u : edg[v]) {
if (redg[v].size() && u == redg[v][0])
continue;
cnt += get_ans_dfs(u, k, ans);
}
cnt += to_root_add[v];
if (cnt >= k)
ans.push_back(rtnum[v]);
return cnt;
}
signed main() {
int n, m, k;
cin >> n >> m >> k;
map<pair<int, int>, int> mp;
for (int i = 1; i < n; ++i) {
int u, v;
cin >> u >> v;
--u, --v;
edg[u].push_back(v);
edg[v].push_back(u);
mp[ghash(u, v)] = i;
}
dfsinit(0, mp);
while (m--) {
int s;
cin >> s;
vector<int> vc(s);
for (int i = 0; i < s; ++i) {
cin >> vc[i];
--vc[i];
}
sort(vc.begin(), vc.end(), cmptin);
int a0 = lca(vc[0], vc[1]);
++to_root_add[vc[0]];
++to_root_add[vc[1]];
to_root_add[a0] -= 2;
for (int i = 2; i < s; ++i) {
int ai = lca(vc[i - 1], vc[i]);
if (depth[ai] >= depth[a0]) {
++to_root_add[vc[i]];
--to_root_add[ai];
a0 = ai;
} else {
++to_root_add[a0];
++to_root_add[vc[i]];
to_root_add[ai] -= 2;
}
}
}
vector<int> ans;
get_ans_dfs(0, k, ans);
cout << ans.size() << '\n';
for (auto x : ans)
cout << x << ' ';
cout << '\n';
}
