#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define f first
#define s second
#define vi vector<int>
#define vvi vector<vector<int>>
#define pi pair<int, int>
#define vpi vector<pi>
#define vvpi vector<vpi>
#define pb push_back
#define mp make_pair
typedef long double ld;
typedef gp_hash_table<int, null_type, hash<int>> ht;
#define ordered_set tree<pair<int, int>, null_type,less<pair<int, int>>, rb_tree_tag,tree_order_statistics_node_update>
const int MX = 1e5 + 5;
const int LOG = 18;
vvpi adj(MX);
vvi tab(MX, vi(LOG));
vi d(MX);
vi num(MX);
vi start(MX), en(MX);
vi seg(2*MX);
int currTime;
void upd(int i, int v) {
seg[i+=MX] += v;
while(i>1) {
i/=2;
seg[i] = seg[2*i] + seg[2*i+1];
}
}
int query(int l, int r) {
l+=MX, r+=MX;
int ans = 0;
while(l<r) {
if(l%2) ans += seg[l++];
if(r%2) ans += seg[--r];
l/=2, r/=2;
}
return ans;
}
int lca(int a, int b) {
if(d[a] < d[b]) swap(a, b);
for(int i=LOG-1;i>=0;i--) {
if(a-(1<<i) >= d[b]) a = tab[a][i];
}
if(a == b) return a;
for(int i=LOG-1;i>=0;i--) {
if(tab[a][i] == tab[b][i]) continue;
a = tab[a][i], b = tab[b][i];
}
return tab[a][0];
}
void dfs(int curr, int par) {
tab[curr][0] = par;
start[curr] = currTime++;
for(auto &next : adj[curr]) {
if(next.f == par) continue;
d[next.f] = d[curr] + 1;
dfs(next.f, curr);
}
en[curr] = currTime++;
}
void dfs2(int curr, int par) {
for(auto &next : adj[curr]) {
if(next.f == par) continue;
dfs2(next.f, curr);
num[curr] += num[next.f];
}
}
bool isPar(int i, int j) { //is i a parent of j
return start[i] <= start[j] && en[i] >= en[j];
}
int main() {
int n, m, k; cin >> n >> m >> k;
for(int i=0;i<n-1;i++) {
int a, b; cin >> a >> b;
--a, --b;
adj[a].pb({b, i});
adj[b].pb({a, i});
}
dfs(0, -1);
for(int i=1;i<LOG;i++) {
for(int j=0;j<n;j++) {
if(tab[j][i-1] == -1) tab[j][i] = -1;
else
tab[j][i] = tab[ tab[j][i-1] ][i-1];
}
}
while(m--) {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int s; cin >> s;
vi in(s);
for(auto &a : in) cin >> a, --a;
int currLca = in[0];
upd(start[in[0]], 1);
for(int i=1;i<in.size();i++) {
int curr = in[i];
if(query(start[curr], en[curr])) {
if(!isPar(currLca, curr)) {
++num[currLca];
--num[curr];
currLca = curr;
}
upd(start[in[i]], 1);
continue;
}
for(int i=LOG-1;i>=0;i--) {
if(tab[curr][i] == -1 || query(start[tab[curr][i]], en[tab[curr][i]])) continue;
curr = tab[curr][i];
}
upd(start[in[i]], 1);
curr = tab[curr][0];
++num[in[i]];
--num[curr];
if(!isPar(currLca, curr)) {
++num[currLca];
--num[curr];
currLca = curr;
}
}
for(auto &a : in) upd(start[a], -1);
}
//propagate all updates
dfs2(0, -1);
vi ans;
for(int i=0;i<n;i++) {
if(num[i] < k) continue;
for(auto &x : adj[i]) {
if(d[x.f] < d[i]) {
ans.push_back(x.s + 1);
}
}
}
cout << ans.size() << "\n";
for(auto &a : ans) cout << a << " ";
cout << "\n";
}
