#include <bits/stdc++.h>
#define FOR(i, begin, end) for(int i = (begin); i < (end); i++)
#define FAST_IO ios_base::sync_with_stdio(false); cin.tie(nullptr)
#define F first
#define S second
#define PB push_back
#define MP make_pair
using namespace std;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef long long ll;
const int INF=1e9;
void setIO()
{
FAST_IO;
}
void setIO(string s)
{
FAST_IO;
freopen((s+".in").c_str(), "r", stdin);
freopen((s+".out").c_str(), "w", stdout);
}
const int N=1e5+10, M=5e4+10, L=27;
int n, m, k, cnt[N], par[N][L], dp[N];
vi ad[N];
map<pii, int> pth, con;
int id;
vi row[M];
unordered_set<int> in[M];
set<pii> inf[M];
void ord(int u, int pst, int idx)
{
if(in[idx].count(u)) inf[idx].insert({id, u});
id++;
for(auto it : ad[u]){
if(it==pst) continue;
ord(it, u, idx);
}
}
void pre(int u, int pst)
{
for(auto it : ad[u]){
if(it==pst) continue;
par[it][0]=u;
dp[it]=dp[u]+1;
pre(it, u);
}
}
int lift(int p, int x)
{
FOR(i, 0, L) if(x&(1<<i))
{
p=par[p][i];
}
return p;
}
int lca(int a, int b)
{
if(dp[a]>dp[b]) swap(a, b);
int dif=dp[b]-dp[a];
b=lift(b, dif);
if(a==b) return a;
for(int i=L-1; i>=0; i--){
if(par[a][i]!=par[b][i]){
a=par[a][i];
b=par[b][i];
}
}
return par[a][0];
}
int sms(int u, int pst)
{
int tot=0;
for(auto it : ad[u]){
if(it==pst) continue;
int k=sms(it, u);
pth[{min(u, it), max(u, it)}]+=k;
tot+=k;
}
return tot+cnt[u];
}
int main()
{
setIO();
cin >> n >> m >> k;
FOR(i, 0, n-1)
{
int a, b;
cin >> a >> b;
ad[a-1].PB(b-1);
ad[b-1].PB(a-1);
con[{min(a-1, b-1), max(a-1, b-1)}]=i+1;
}
pre(0, -1);
FOR(i, 1, L)
{
FOR(j, 0, n)
{
par[j][i]=par[par[j][i-1]][i-1];
}
}
FOR(i, 0, m)
{
int s;
cin >> s;
//in.clear();
//row.clear();
//inf.clear();
id=0;
FOR(j, 0, s)
{
int x;
cin >> x;
in[i].insert(x-1);
cnt[x-1]++;
}
ord(0, -1, i);
/*
FOR(i, 0, (int)inf.size())
{
int b=lca(inf[i].S, inf[(i+1)%(int)inf.size()].S);
cnt[b]--;
}
*/
pii lst={-1, -1}, nd;
for(auto it : inf[i]){
if(lst.F==-1){
lst=it;
nd=it;
continue;
}
int b=lca(lst.S, it.S);
cnt[b]--;
lst=it;
nd=it;
}
pii st=*inf[i].begin();
int b=lca(st.S, nd.S);
cnt[b]--;
}
sms(0, -1);
vi ans;
for(auto it : pth){
if(it.S>=k){
ans.PB(con[{min(it.F.F, it.F.S), max(it.F.F, it.F.S)}]);
}
}
cout << ans.size() << '\n';
for(auto x : ans){
cout << x << " ";
}
}
