// :)
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pll;
//-----------------debug--------------------------
vector<string> vec_splitter(string s) {
s += ',';
vector<string> res;
while(!s.empty()) {
res.push_back(s.substr(0, s.find(',')));
s = s.substr(s.find(',') + 1);
}
return res;
}
void debug_out(
vector<string> __attribute__ ((unused)) args,
__attribute__ ((unused)) int idx,
__attribute__ ((unused)) int LINE_NUM) { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(vector<string> args, int idx, int LINE_NUM, Head H, Tail... T) {
if(idx > 0) cerr << ", "; else cerr << "Line(" << LINE_NUM << ") ";
stringstream ss; ss << H;
cerr << args[idx] << " = " << ss.str();
debug_out(args, idx + 1, LINE_NUM, T...);
}
#define deb(...) debug_out(vec_splitter(#__VA_ARGS__), 0, __LINE__, __VA_ARGS__)
template <class T1, class T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
return os << '{' << p.first << ", " << p.second << '}';
}
template <class T, class = decay_t<decltype(*begin(declval<T>()))>,
class = enable_if_t<!is_same<T, string>::value>>
ostream &operator<<(ostream &os, const T &c) {
os << '[';
for (auto it = c.begin(); it != c.end(); ++it)
os << &", "[2 * (it == c.begin())] << *it;
return os << ']';
}
//support up to 5 args
#define _NTH_ARG(_1, _2, _3, _4, _5, _6, N, ...) N
#define _FE_0(_CALL, ...)
#define _FE_1(_CALL, x) _CALL(x)
#define _FE_2(_CALL, x, ...) _CALL(x) _FE_1(_CALL, __VA_ARGS__)
#define _FE_3(_CALL, x, ...) _CALL(x) _FE_2(_CALL, __VA_ARGS__)
#define _FE_4(_CALL, x, ...) _CALL(x) _FE_3(_CALL, __VA_ARGS__)
#define _FE_5(_CALL, x, ...) _CALL(x) _FE_4(_CALL, __VA_ARGS__)
#define FOR_EACH_MACRO(MACRO, ...) \
_NTH_ARG(dummy, ##__VA_ARGS__, _FE_5, _FE_4, _FE_3, _FE_2, _FE_1, _FE_0) \
(MACRO, ##__VA_ARGS__)
//Change output format here
#define out(x) #x " = " << x << "; "
#define debug(...) \
cerr << "Line " << __LINE__ << ": " FOR_EACH_MACRO(out, __VA_ARGS__) << endl
//----------------------------------------------
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define FIO ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define no cout << "NO\n"; return;
#define yes cout << "YES\n"; return;
#define SP fixed << setprecision(10)
//FILE *fin = freopen("in","r",stdin);
//FILE *fout = freopen("out","w",stdout);
const ll mod = 1e9+7;
const ll oo = 1e18;
const ll N = 1e5*2 + 10, N2 = 1e6;
ll n, m, k, ans;
vector<ll> g[N];
ll cnt[N], re[N], sz[N], mx[N], a[N];
vector<ll> t[N];
void get_sz(ll v, ll fa){
sz[v]=t[v].size()+1;
for(auto u : g[v]){
if(u==fa) continue;
get_sz(u, v); sz[v]+=sz[u];
}
}
void cle(ll v, ll fa){
for(auto c:t[v])
cnt[c]=0;
for(auto u : g[v])
if(u!=fa) cle(u, v);
}
ll sum = 0;
void add(ll c){
cnt[c]++;
if(cnt[c]==1) sum++;
if(cnt[c]==mx[c]) sum--;
}
void ade(ll v, ll fa){
for(auto c : t[v])
add(c);
for(auto u : g[v])
if(u!=fa) ade(u, v);
}
map<pll, ll> dd;
void dfs(ll v, ll fa, ll tt = 0){
sum = 0;
pll mx = {0, -1};
for(auto u : g[v]) if(u!=fa)
mx = max(mx, {sz[u], u});
for(auto u : g[v])
if(u!=mx.ss && u!=fa) dfs(u, v);
if(mx.ss != -1) dfs(mx.ss, v, 1);
for(auto c:t[v])
add(c);
for(auto u : g[v])
if(u!=mx.ss && u!=fa) ade(u, v);
dd[mp(v, fa)]=sum;
if(tt==0){
cle(v, fa);
sum = 0;
}
}
vector<pll> ms;
void code(){
get_sz(1, 1);
dfs(1, 1, 1);
vector<ll> ans;
for(int i = 0; i < ms.size(); i++){
ll su = dd[mp(ms[i].ff, ms[i].ss)];
su += dd[mp(ms[i].ss, ms[i].ff)];
if(su >= k) ans.pb(i+1);
}
cout<< ans.size()<<"\n";
for(auto u : ans) cout<< u<<" ";
}
int main(){
FIO;
cin>> n>> m>> k;
for(int i = 1; i < n; i++){
ll v, u; cin>> v>> u;
g[v].pb(u); g[u].pb(v);
ms.pb({v,u}) ;
}
for(int i = 1; i <= m; i++){
ll si; cin>> si;
mx[i] = si;
while(si--){
ll x; cin>> x;
t[x].pb(i);
}
}
code();
}
