#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ll long long
#define all(x) x.begin(), x.end()
#define ins insert
#define pb push_back
#define F first
#define S second
#define bt bitset<5010>
const int N = 1e5 + 100, K = 1610;
const int mod = 998244353;
vector<pair<int, int>>g[N];
vector<int>g1[N];
int f[N], tin[N], tout[N], timer, up[N][20];
int n, m, k;
void dfs(int v, int p){
tin[v] = timer++;
up[v][0] = p;
for(int i = 1; i < 20; i++){
up[v][i] = up[up[v][i - 1]][i - 1];
}
for(auto [to, idx] : g[v]){
if(to == p) continue;
dfs(to, v);
}
tout[v] = timer;
}
int F(int u, int v){
return tin[u] <= tin[v] && tout[v] <= tout[u];
}
int lca(int u, int v){
if(F(u, v)) return u;
if(F(v, u)) return v;
for(int i = 19; i >= 0; i--){
if(!F(up[u][i], v)) u = up[u][i];
}
return up[u][0];
}
void add(int idx, int vl){
for(; idx < N; idx |= (idx + 1)){
f[idx] += vl;
}
}
int get(int r){
int res = 0;
for(; r >= 0; r = (r & (r + 1)) - 1){
res += f[r];
}
return res;
}
int get(int l, int r){
return get(r - 1) - get(l - 1);
}
void Path(int v, int l, int vl){
add(tin[l], -vl);
add(tin[v], vl);
}
void V(int v, int vl){
add(tin[v], vl);
if(up[v][0] != v) add(tin[up[v][0]], -vl);
}
int getV(int v){
return get(tin[v], tout[v]);
}
bool cmp(int x, int y){
return tin[x] < tin[y];
}
void dfs1(int v, int p){
for(auto to : g1[v]){
Path(to, v, 1);
dfs1(to, v);
}
}
void build(vector<int>v){
int z = v.size();
sort(all(v), cmp);
for(int i = 0; i < z - 1; i++){
v.pb(lca(v[i], v[i + 1]));
}
sort(all(v), cmp);
v.erase(unique(all(v)), v.end());
vector<int>v1;
z = v.size();
for(int i = 0; i < z; i++){
int u = v[i];
while(v1.size() >= 2 && !F(v1.back(), u)){
g1[v1[v1.size() - 2]].pb(v1.back());
v1.pop_back();
}
v1.pb(u);
}
while(v1.size() >= 2){
g1[v1[v1.size() - 2]].pb(v1.back());
v1.pop_back();
}
dfs1(v1[0], v1[0]);
for(auto it : v){
g1[it].clear();
}
}
void solve(){
cin>>n>>m>>k;
for(int i = 1; i <= n - 1; i++){
int u, v;
cin>>u>>v;
g[u].pb({v, i});
g[v].pb({u, i});
}
dfs(1, 1);
for(int i = 1; i <= m; i++){
vector<int>v;
int z;
cin>>z;
for(int j = 1; j <= z; j++){
int x;
cin>>x;
v.pb(x);
}
build(v);
}
vector<int>ans;
for(int i = 2; i <= n; i++){
if(getV(i) >= k){
for(auto [to, idx] : g[i]){
if(to == up[i][0]) ans.pb(idx);
}
}
}
cout<<ans.size()<<'\n';
for(auto it : ans) cout<<it<<' ';
}
main(){
ios_base :: sync_with_stdio(false);
cin.tie(nullptr);
int t = 1;
//cin>>t;
while(t--){
solve();
}
}
