#include <bits/stdc++.h>
typedef long long int ll;
typedef long double ld;
#define pb push_back
#define pii pair < ll , ll >
#define F first
#define S second
#define endl '\n'
#define int long long
#define sync ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#pragma GCC optimize ("Ofast")
#pragma GCC optimize ("unroll-loops")
using namespace std;
/// khodaya komak kon
/// ya navid navid
const int N=2e5+100,M=22;
vector <int> g[N];
ll par[N][22];
ll hi[N];
ll st[N];
ll fn[N],tss=1;
ll dfs(ll v,ll p,ll h){
hi[v]=h;
st[v]=tss;
for (int i=0;i<g[v].size();i++){
ll u=g[v][i];
if (u==p) continue;
par[u][0]=v;
tss++;
dfs(u,v,h+1);
}
tss++;
fn[v]=tss;
}
ll getpar(ll v,ll h){
if (h==-1 || h==0){
return v;
}
for(int i=0;i<M;i++){
if (h & (1 << i)) v = par[v][i];
}
return v;
}
int lca(int v, int u) {
if (hi[v]<hi[u]){
ll y=v;
v=u;
u=y;
}
v = getpar(v,hi[v]-hi[u]);
if (v==u){
return v;
}
for(int i=20;i>=0;i--){
if (par[v][i] != par[u][i]) {
v=par[v][i];
u=par[u][i];
}
}
return par[v][0];
}
ll vis[N];
ll val[N];
ll dp[N];
ll dfss(ll v,ll p){
dp[v]=val[v];
for (int i=0;i<g[v].size();i++){
ll u=g[v][i];
if (u==p) continue;
dfss(u,v);
dp[v]+=dp[u];
}
}
map <pii,int> mp;
int32_t main(){
ll n,m,k;
cin >> n >> m >> k;
for (int i=0;i<n-1;i++){
ll u,v;
cin >> u >> v;
g[v].pb(u);
g[u].pb(v);
mp[{u,v}]=i+1;
mp[{v,u}]=i+1;
}
dfs(1,1,1);
par[1][0]=1;
for (int i=1;i<M;i++){
for (int j=1;j<=n;j++){
par[j][i]=par[par[j][i-1]][i-1];
}
}
for (int i=0;i<m;i++){
ll x;
cin >> x;
vector <pair <pii,int> > a,d;
for (int j=0;j<x;j++){
ll v;
cin >> v;
a.pb({{st[v],fn[v]},v});
}
sort(a.begin(),a.end());
for (int i=0;i<a.size();i++){
vis[a[i].S]=1;
d.pb(a[i]);
}
if (a.size()){
a.pb(a[0]);
}
for (int i=1;i<a.size();i++){
ll v=a[i].S,u=a[i-1].S;
ll f=lca(v,u);
//cout << v << " " << u << " f " << f << endl;
if (!vis[f]) d.pb({{st[f],fn[f]},f});
vis[f]=1;
}
sort(d.begin(),d.end());
vector <pii> b;
b.pb({1e9+100,0});
for (int i=0;i<d.size();i++){
while(d[i].F.S>=b.back().F) b.pop_back();
ll v=b.back().S;
if (v!=0){
/// yrkari monde
val[d[i].S]++;
val[v]--;
//cout << d[i].S << " yal " << v << endl;
}
b.pb({d[i].F.S,d[i].S});
}
for (int i=0;i<d.size();i++){
vis[d[i].S]=0;
}
}
dfss(1,1);
ll ans=0;
vector <int> p;
for (int i=1;i<=n;i++){
if (dp[i]>=k){
ans++;
p.pb(mp[{i,par[i][0]}]);
}
}
sort(p.begin(),p.end());
cout << ans << endl;
for (int i=0;i<p.size();i++){
cout << p[i] << " " ;
}
}
