/*#pragma GCC target ("avx2")
#pragma GCC optimize ("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")/**/
#include<bits/stdc++.h>
/**/
//typedef int ll;
typedef long long ll;
typedef unsigned long long ull;
typedef std::string str;
//typedef vector<std::vector<ll>> vv;
/*typedef __int128 vll;
typedef unsigned __int128 uvll;*/
#define llll std::pair<ll , ll>
#define pb push_back
#define pf push_front
#define halo cout << "hello\n"
#define fi first
#define sec second
#define vv(x) std::vector<std::vector<x>>
#define all(a) a.begin() , a.end()
const ll limit = 1e9+7;
const ll ous = 3e5 + 7;
const ll dx[4] = {-1 , 0 , 1 , 0} , dy[4] = {0,1,0,-1};
ll n , m , k;std::vector<ll> ar , par , kt , fs(ous , 0) , tb(ous , 0) , lev(ous , 0) , lg2(ous , 0);
std::vector<ll> dspar(ous , 0) , dssz(ous , 0) , dsval(ous , 0) , gk(ous , 0);
std::vector<llll> adj[ous] , scpar;
std::vector<std::vector<ll>> spar(ous , std::vector<ll>(20 , 0));
ll tmr = 0;
ll fnd(ll x){
if(x == dspar[x]){
return x;
}
return dspar[x] = fnd(dspar[x]);
}
void mrg(ll x , ll y){
x = fnd(x);y = fnd(y);
if(x != y){
if(dssz[y] > dssz[x]){
std::swap(x , y);
}
dssz[x] += dssz[y];
dspar[y] = x;
}
}
void dfs(ll cur , ll prv){
tmr++;
lev[cur] = lev[prv] - 1;
ll k = tmr;
tb[k] = cur;
fs[cur] = ar.size();
spar[ar.size()][0] = k;
ar.pb(k);
for(auto j:adj[cur]){
if(j.fi != prv){
par[j.fi] = j.sec;
dfs(j.fi , cur);
}
spar[ar.size()][0] = k;
ar.pb(k);
}
}
bool cmp(ll x , ll y){
return fs[x] < fs[y];
}
void sdfs(ll crt , ll prv){
for(auto j:adj[crt]){
if(j.fi != prv){
sdfs(j.fi , crt);
}
}
gk[par[crt]]+= kt[crt];
kt[prv]+=kt[crt];
}
void solve(){
std::cin >> n >> m >> k;
par.resize(n+5);
kt.resize(n+5);
lg2[1] = 0;
for(ll i = 2;ous > i;i++){
lg2[i] = lg2[i/2] + 1;
}
for(ll i = 1;n>i;i++){
ll x , y;std::cin >> x >> y;
adj[x].pb({y , i});
adj[y].pb({x , i});
}
dfs(1 , 0);
for(ll j = 1;20>j;j++){
for(ll i = 0;ar.size()>i + (1 << j);i++){
spar[i][j] = std::min(spar[i][j-1] , spar[i + (1 << j-1)][j-1]);
}
}
//std::cout << spar[0][0] << "\n";
for(ll i = 0;m>i;i++){
ll x;std::cin >> x;
std::vector<ll> o;
for(ll j = 0;x>j;j++){ll y;std::cin >> y;o.pb(y);kt[y]++;}
std::sort(all(o) , cmp);
std::set<std::pair<llll , llll>> st;
for(ll j = 0;x>j;j++){
dsval[j] = o[j];
dspar[j] = j;
dssz[j] = 1;
}
ll alc = o[0];
for(ll j = 1;x > j;j++){
ll mn = std::min(fs[o[j-1]] , fs[o[j]]) , mx = std::max(fs[o[j-1]] , fs[o[j]]);
ll tt = lg2[mx - mn + 1];
ll lc = std::min(spar[mn][tt] , spar[mx - (1ll << tt) + 1][tt]);
ll pt = tb[lc];
mn = std::min(fs[alc] , fs[o[j]]) , mx = std::max(fs[alc] , fs[o[j]]);
tt = lg2[mx - mn + 1];
lc = std::min(spar[mn][tt] , spar[mx - (1ll << tt) + 1][tt]);
alc = tb[lc];
//std::cout << pt << " " << dsval[j] << " " << dsval[j-1] << "\n";
st.insert({{lev[pt] , pt} , {j , j-1}});
}
kt[alc]--;
while(st.size()){
std::pair<llll , llll> a = *st.begin();
st.erase(st.begin());
ll x = fnd(a.sec.fi) , y = fnd(a.sec.sec);
if(x != a.sec.fi || y != a.sec.sec){
ll mn = std::min(fs[dsval[x]] , fs[dsval[y]]) , mx = std::max(fs[dsval[x]] , fs[dsval[y]]);
ll tt = lg2[mx - mn + 1];
ll lc = std::min(spar[mn][tt] , spar[mx - (1ll << tt) + 1][tt]);
ll o = tb[lc];
st.insert({{lev[o] , o} , {x , y}});
}
else{
mrg(a.sec.fi , a.sec.sec);
dsval[fnd(a.sec.fi)] = a.fi.sec;
//std::cout << a.fi.fi << " " << a.fi.sec << " " << dsval[a.sec.fi] << " " << dsval[a.sec.sec] << "\n";
kt[a.fi.sec]--;
}
}
}
sdfs(1 , 0);
std::vector<ll> ans;
for(ll i = 1;n>i;i++){
if(gk[i] >= k){
ans.pb(i);
//std::cout << i << "\n";
}
}
std::cout << ans.size() << "\n";
for(auto j:ans){
std::cout << j << " ";
}
std::cout <<"\n";
return;/**/
}
signed main(){
std::ios_base::sync_with_stdio(false);std::cin.tie(NULL);
ll t=1;
//std::cin >> t;
ll o = 1;
while(t--){
//cout << "Case " << o++ << ":\n";
solve();
}
return 0;
}/**/
