#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pi pair<int, int>
#define pii pair<int, pi>
#define fi first
#define se second
int sz[1000005], head[1000005], par[1000005], dep[1000005], S[1000005];
int up[1000005];
vector<int>v[1000005];
int n, q;
vector<pii>adj;
int getr(int x){
return (par[x] == x ? x : par[x] = getr(par[x]));
}
void merge(int a, int b){
a = getr(a), b = getr(b);
if(a != b)par[b] = a;
}
void dfs(int x, int p, int d){
dep[x] = d;
up[x] = p;
sz[x] = 1;
for(auto i : v[x]){
if(i == p)continue;
dfs(i, x, d + 1);
sz[x] += sz[i];
}
}
struct node{
int s,e,m,val, lazy = 0;
node *l, *r;
node(int _s, int _e){
s = _s, e = _e, m = (s + e)>>1;
val = 0;
if(s != e)l = new node(s, m), r = new node(m+1, e);
}
void propo(){
if(lazy){
val += lazy * (e - s + 1);
if(s != e)l->lazy += lazy, r->lazy += lazy;
lazy = 0;
}
}
void upd(int a, int b, int c){
//cerr << "UPD " << a << " " << b << " " << c << '\n';
if(a == s && b == e)lazy += c;
else{
if(b <= m)l->upd(a, b, c);
else if(a > m)r->upd(a, b, c);
else l->upd(a, m, c), r->upd(m+1, b, c);
l->propo(), r->propo();
val = l->val + r->val;
}
}
int query(int a, int b){
propo();
if(a == s && b == e)return val;
else if( b <= m)return l->query(a, b);
else if(a > m)return r->query(a, b);
else return (l->query(a, m) + r->query(m+1, b));
}
}*root;
int cnt = 1;
void dfs2(int x, int h, int par){
S[x] = cnt++;
head[x] = h;
int maxi = 0, in = -1;
for(auto i : v[x]){
if(i == par)continue;
if(maxi < sz[i])maxi = sz[i], in = i;
}
for(auto i : v[x]){
if(i == par)continue;
if(i == in)dfs2(i, h, x);
}
for(auto i : v[x]){
if(i != par && i != in)dfs2(i, i, x);
}
}
vector <pi> upds;
void chng(int a, int b) {
for (; head[a] != head[b]; b = up[head[b]]) {
//cerr << a << " " << b << " " << head[a] << " " << head[b] << '\n';
if (dep[head[a]] > dep[head[b]])
swap(a, b);
//root->upd(S[head[b]], S[b], 1);
upds.push_back({S[head[b]], S[b]});
}
if (dep[a] > dep[b])
swap(a, b);
if(S[a] != S[b])upds.push_back({S[a] + 1, S[b]});//root->upd(S[a]+1, S[b], 1);
}
int query(int a, int b) {
int res = 0;
for (; head[a] != head[b]; b = up[head[b]]) {
if (dep[head[a]] > dep[head[b]])
swap(a, b);
int cur_heavy_path_max = root->query(S[head[b]], S[b]);
res += cur_heavy_path_max;
}
if (dep[a] > dep[b])
swap(a, b);
if(S[a] != S[b])res += root->query(S[a]+1, S[b]);
return res;
}
int k;
int A[200005], B[200005];
int32_t main(){
ios::sync_with_stdio(0);cin.tie(0);
cin >> n >> q >> k;
for(int i=1;i<n;i++){
int x, y; cin >> x >> y;
v[x].push_back(y);
v[y].push_back(x);
A[i] = x, B[i] = y;
}
root= new node(1, n);
dfs(1, -1, 1);
//cerr << "ok\n";
dfs2(1, 1, -1);
while(q--){
int x; cin >> x;
int prv = -1;
while(x--){
int a; cin >> a;
if(prv != -1)chng(prv, a);
prv = a;
}
sort(upds.begin(), upds.end());
int mx = 0;
for(auto [i, j] : upds){
if(mx >= j)continue;
root->upd(max(mx + 1, i), j, 1);
mx = max(mx, j);
}
upds.clear();
}
vector <int> ans;
for(int i=1;i<n;i++){
if(query(A[i], B[i]) >= k)ans.push_back(i);
}
cout << (int)ans.size() << '\n';
for(auto i : ans)cout << i << ' ';
}
