#include <bits/stdc++.h>
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
using namespace std;
using ll = long long;
const ll mod = 998244353;
#define fi first
#define se second
#define rep(i,n) for(ll i=0;i<n;i++)
#define all(x) x.begin(),x.end()
#define faster ios::sync_with_stdio(false);cin.tie(nullptr)
using Graph = vector<vector<ll>>;
struct LCA{
vector<vector<ll>> par;
vector<ll> dis;
LCA(const Graph &G,ll root=0){init (G,root);}
void init(const Graph &G,ll root=0){
ll v=G.size();
ll k=1;
while((1<<k)<v) k++;
par.assign(k,vector<ll>(v,-1));
dis.assign(v,-1);
dfs(G,root,-1,0);
for(ll i=0;i+1<k;i++){
for(ll j=0;j<v;j++){
if(par[i][j]<0) par[i+1][j]=-1;
else par[i+1][j]=par[i][par[i][j]];
}
}
}
void dfs(const Graph &G,ll v,ll p,ll d){
par[0][v]=p;
dis[v]=d;
for(ll nv:G[v]){
if(nv!=p) dfs(G,nv,v,d+1);
}
}
ll query(ll u,ll v){
if(dis[u]<dis[v]) swap(u,v);
ll K=par.size();
for(ll k=0;k<K;k++){
if((dis[u]-dis[v])>>k&1){
u=par[k][u];
}
}
if(u==v) return u;
for(ll k=K-1;k>=0;k--){
if(par[k][u]!=par[k][v]){
u=par[k][u];
v=par[k][v];
}
}
return par[0][u];
}
ll get_dis(ll u,ll v){return dis[u]+dis[v]-2*dis[query(u,v)];}
};
vector<ll> bfs(vector<vector<ll>> G){
ll N=G.size();
vector<ll> dis(N,-1);
dis[0]=0;
queue<ll> que;
que.push(0);
while(!que.empty()){
ll v=que.front();
que.pop();
for(ll nv:G[v]){
if(dis[nv]!=-1) continue;
dis[nv]=dis[v]+1;
que.push(nv);
}
}
return dis;
}
int main() {
ll N,Q,K;
cin >> N >> Q >> K;
vector<ll> A(N-1),B(N-1);
Graph G(N);
rep(i,N-1){
cin >> A[i] >> B[i];
A[i]--,B[i]--;
G[A[i]].push_back(B[i]);
G[B[i]].push_back(A[i]);
}
vector<ll> dis=bfs(G);
vector<ll> Eid(N,-1);
rep(i,N-1){
if(dis[A[i]]>dis[B[i]]) Eid[A[i]]=i;
if(dis[B[i]]>dis[A[i]]) Eid[B[i]]=i;
}
ll cnt=0;
vector<ll> Vid(N);
function<void(ll)> dfs=[&](ll v){
Vid[v]=cnt;
cnt++;
for(ll nv:G[v]){
if(dis[nv]<dis[v]) continue;
dfs(nv);
}
};
dfs(0);
vector<ll> imos(N,0);
LCA ans(G);
while(Q--){
ll M;
cin >> M;
vector<pair<ll,ll>> P(M);
rep(i,M){
ll v;
cin >> v;
v--;
P[i].fi=Vid[v];
P[i].se=v;
}
sort(all(P));
rep(i,M){
ll x=P[i].se;
ll y=P[(i+1)%M].se;
ll z=ans.query(x,y);
imos[x]+=1;
imos[y]+=1;
imos[z]-=2;
}
}
function<void(ll)> sum=[&](ll v){
ll par=-1;
for(ll nv:G[v]){
if(dis[nv]<dis[v]){
par=nv;
continue;
}
sum(nv);
}
if(par>=0) imos[par]+=imos[v];
};
sum(0);
vector<ll> ANS;
rep(i,N){
if(imos[i]>=K*2) ANS.push_back(Eid[i]+1);
}
sort(all(ANS));
cout << ANS.size() << endl;
rep(i,ANS.size()){
cout << ANS[i] << " ";
}
cout << endl;
return 0;
}
