#include <bits/stdc++.h>
using namespace std;
template<class ISqr, class T>
ISqr& operator>>(ISqr& is, vector<T>& v) { for (auto& x : v) is >> x; return is; }
#define SPEED \
ios_base::sync_with_stdio(0); \
cin.tie(NULL); \
cout.tie(NULL);
#define print(v) \
for(auto& u : v) cout << u << " "; \
cout << endl;
#define pb push_back
#define ins insert
#define fi first
#define er erase
#define se second
#define vi vector<int>
#define gi greater<int>
#define pii pair<int, int>
#define vpii vector<pair<int, int>>
#define endl "\n"
#define yes cout << "yes" << endl
#define no cout << "no" << endl
#define ALL(x) x.begin(), x.end()
#define sz(x) x.size()
#define impos cout << -1 << endl;
#define int long long
#define _ << " " <<
const int mod = 998244353;
const int inf = 1e18;
const int p = 47;
const int LOG = 11;
const int sz = 2e5 + 5;
vector<vi>graph(sz), up;
int timer, n, L;
vi giris(sz), cixis(sz), depth(sz), sub(sz), deg(sz);
void dfs(int node, int parent) {
giris[node] = timer++;
if(node != parent) {
depth[node] = depth[parent] + 1;
}
up[node][0] = parent;
for(int i=1;i <= L;i++){
up[node][i] = up[up[node][i-1]][i-1];
}
for(auto u : graph[node]) {
if(u != parent) {
dfs(u, node);
}
}
cixis[node] = timer++;
}
bool check_ancestor(int a, int b) {
if(giris[a] <= giris[b] && cixis[a] >= cixis[b]) return true;
return false;
}
int lca(int a, int b) {
if(check_ancestor(a,b)) return a;
if(check_ancestor(b,a)) return b;
for(int i = L; i >= 0; i--) {
if(!check_ancestor(up[a][i], b)) a = up[a][i];
}
return up[a][0];
}
int tt;
void dfs2(int node, int parent = -1) {
tt++;
for(auto u : graph[node]) {
if(u != parent) {
// cout << "DFS: " << u << " " << node << " " << tt << endl;
dfs2(u, node);
// cout << "DFSS: " << u << " " << node << " "<< tt << endl;
sub[node] += sub[u];
}
}
}
void solve() {
int n, m, k;
cin >> n >> m >> k;
graph.resize(n+1);
giris.assign(n+1, 0);
cixis.assign(n+1, 0);
L = ceil(log2(n));
up.assign(n+1, vi(L+1));
sub.resize(n+1);
timer = 0;
// cout << "ISLEYIREM" << endl;
vi recs; vpii edges;
for(int i = 1; i < n; i++) {
int a, b;
cin >> a >> b;
graph[a].pb(b);
graph[b].pb(a);
++deg[a]; ++deg[b];
edges.pb({a,b});
}
// cout << "IISLEYIREM" << endl;
int root = 0;
for(int i = 1; i <= n; i++) {
if(deg[i] == 1) {
root = i;
break;
}
}
// cout << "Root: " << root << endl;
// cout << "IIISLEYIREM" << endl;
dfs(root, root);
// cout << "IIIISLEYIREM" << endl;
for(int i = 0; i < m; i++) {
int s;
cin >> s;
vi cock(s);
cin >> cock;
sort(ALL(cock),[&](int a, int b){
return giris[a] < giris[b];
});
cock.pb(cock[0]);
for(int j = 0; j < s; j++) {
sub[cock[j]]++;
sub[cock[j+1]]++;
sub[lca(cock[j],cock[j+1])] -= 2;
}
}
// for(int i = 1; i <= n; i++) {
// cout << "Init: " << i << " " << sub[i] << endl;
// }
// cout << "IIIISLEYIREM" << endl;
dfs2(root);
// cout << "IIIIISLEYIREM" << endl;
// for(int i = 1; i <= n; i++) {
// cout << i << " " << sub[i] << endl;
// }
// cout << endl;
set<pii>cockset;
for(int i = 1; i <= n; i++) {
if(sub[i] >= 2 * k) {
cockset.ins({min(i, up[i][0]), max(i, up[i][0])});
}
}
int ind = 0;
for(auto u : edges) {
bool checker = cockset.count({min(u.fi,u.se),max(u.fi,u.se)});
if(checker) recs.pb(ind+1);
ind++;
}
cout << sz(recs) << endl;
for(int i : recs) cout << i << " ";
cout << endl;
}
signed main() {
SPEED;
int tst = 1;
// cin >> tst;
for (int cs = 1; cs <= tst; cs++) {
solve();
}
// cerr << "Time Elapsed: " << (long double)clock() << eel;
}
