#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vb = vector<bool>;
using vvb = vector<vb>;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vc = vector<char>;
using vvc = vector<vc>;
using vs = vector<string>;
const ll mod = 1e9 + 7,inf = 1e18;
#define pb push_back
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
void setIO()
{
fast;
}
int n = 1e5 + 5,m,k,TIMER;
vvi adj(n),anc(n,vi(21));
vi pref(n),in(n),out(n);
void dfs(int u,int p)
{
in[u] = ++TIMER;
anc[u][0] = p;
for (int i = 1;i<=20;i++)anc[u][i] = anc[anc[u][i - 1]][i - 1];
for (int v:adj[u]){
if (v == p)continue;
dfs(v,u);
}
out[u] = ++TIMER;
}
void dfs2(int u,int p)
{
for (int v:adj[u]){
if (v == p)continue;
dfs2(v,u);
pref[u] += pref[v];
}
}
bool cmp(int a,int b)
{
return in[a] <= in[b];
}
bool is_ancestor(int u,int v)
{
return in[u] <= in[v] && out[u] >= out[v];
}
int LCA(int u,int v)
{
if (in[u] > in[v])swap(u,v);
if (is_ancestor(u,v))return u;
for (int i = 20;i>=0;i--)
if (!is_ancestor(anc[v][i],u))v = anc[v][i];
return anc[v][0];
}
int main()
{
setIO();
cin>>n>>m>>k;
for (int i = 1;i<n;i++){int u,v;cin>>u>>v;adj[u].pb(v),adj[v].pb(u);}
dfs(1,1);
while (m--){
int num;
cin>>num;
vi vals(num);
for (int i = 0;i<num;i++)cin>>vals[i];
sort(vals.begin(),vals.end(),cmp);
// for (int i = 0;i<num - 1;i++){
// cout<<vals[i]<<" "<<vals[i + 1]<<" "<<LCA(vals[i],vals[i + 1])<<'\n';
// }
// cout<<'\n';
for (int i = 0;i<num;i++){
int lca = LCA(vals[i],vals[(i + 1)%num]);
pref[vals[i]]++;
pref[vals[(i + 1)%num]]++;
pref[lca] -= 2;
}
}
dfs2(1,1);
vi all;
for (int i = 1;i<=n;i++)if (pref[i] >= 2 * k)all.pb(i);
cout<<all.size()<<'\n';
for (auto it:all)cout<<it<<" ";
return 0;
}
