#include <bits/stdc++.h>
using namespace std;
#define sz(v) (int)v.size()
#define fi first
#define sc second
const int MAXN = 1e5+5, MAX = 17;
vector<int> adj[MAXN], id[MAXN];
int pai[MAXN], pid[MAXN], dist[MAXN], tin[MAXN], tout[MAXN], bit[MAXN], sparse[MAX+5][MAXN], n , t;
void update(int i, int x){
for(; i <= n; i += i&-i)
bit[i] += x;
}
int query(int i){
if(i <= 0)return 0;
int ans = 0;
for(; i > 0; i-= i&-i)
ans += bit[i];
return ans;
}
void dfsIni(int s){
t++; tin[s] = t;
for(int i = 0; i < sz(adj[s]); i++){
int viz = adj[s][i];
if(viz != pai[s]){
sparse[0][viz] = s;
pai[viz] = s;
dist[viz] = dist[s]+1;
pid[viz] = id[s][i];
dfsIni(viz);
}
}
tout[s] = t;
}
int lca(int a, int b){
if(dist[a] < dist[b])swap(a,b);
int d = dist[a]-dist[b];
for(int i = 0; i < MAX; i++)
if(d & (1<<i))a = sparse[i][a];
if(a == b)return a;
for(int i = MAX; i >= 0; i--)
if(sparse[i][a] != sparse[i][b]){
a = sparse[i][a];
b = sparse[i][b];
}
return sparse[0][a];
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int m,k; cin>>n>>m>>k;
for(int i = 1; i < n; i++){
int a,b; cin>>a>>b;
adj[a].push_back(b); id[a].push_back(i);
adj[b].push_back(a); id[b].push_back(i);
}
dfsIni(1);
for(int i = 1; i <= MAX; i++)
for(int j = 1; j <= n; j++)
if(sparse[i-1][j] != 0)sparse[i][j] = sparse[i-1][sparse[i-1][j]];
for(int i = 1; i <= m; i++){
int s; cin>>s;
vector< pair<int,int> > o;
for(int j = 1; j <= s; j++){
int v; cin>>v;
o.emplace_back(tin[v], v);
}
sort(o.begin(),o.end());
for(int j = 0; j < s-1; j++){
update( o[j].fi, 1);
update( o[j+1].fi, 1);
update( tin[ lca(o[j].sc, o[j+1].sc)] , -2);
}
update( o[s-1].fi, 1);
update( o[0].fi, 1);
update( tin[ lca(o[s-1].sc, o[0].sc)] , -2);
}
vector<int> ans;
for(int i = 2; i <= n; i++)
if(query(tout[i])-query(tin[i]-1) >= 2*k)ans.push_back(pid[i]);
sort(ans.begin(),ans.end());
cout<<sz(ans)<<"\n";
for(auto it : ans)cout<<it<<" ";
cout<<"\n";
}
