#include "bits/stdc++.h"
using namespace std;
#define ll long long
#define f first
#define s second
#define pi pair<ll,ll>
#define vi vector<ll>
#define vd vector<double>
#define vpi vector<pi>
#define pb push_back
#define INF 1e18
#define endl '\n'
//#define int ll
#define pii pair<pi,ll>
const int mod = 1e9+7;
const int MAX = 1e5+1;
const int LOG = 30;
vi g[MAX];
int tin[MAX], val[MAX], tout[MAX];
int up[LOG+1][MAX];
map<pi,int>mp;
vector<pi>order;
int timer = 0;
void dfs(int from,int pr){
tin[from]= ++timer;
up[0][from] = pr;
for(int i=1 ; i <= LOG; i++){
up[i][from] = up[i-1][up[i-1][from]];
}
for(int to :g[from]){
if(to==pr) continue;
dfs(to,from);
}
tout[from]=++timer;
}
bool anc(int u,int v){
return tin[u]<=tin[v] && tout[u]>=tout[v];
}
ll dfs1(int from,int pr){
ll sum = val[from];
ll hk;
for(int to :g[from]){
if(to==pr) continue;
hk = dfs1(to,from);
sum+=hk;
int a = min(from,to);
int b = max(from,to);
mp[{a,b}]+=hk;
}
return sum;
}
int lca(int u, int v){
if(anc(u,v)) return u;
if(anc(v,u)) return v;
for(int i = LOG; i >= 0; i--){
if(anc(up[i][u], v)) continue;
u= up[i][u];
}
return up[0][u];
}
signed main(){
int n,m,k,a,b;
cin >>n >> m >> k;
for(int i =1; i<n; i++){
cin >> a >> b;
g[a].pb(b);
g[b].pb(a);
order.pb({a,b});
}
int q;
dfs(1,1);
for(int i =0; i < m; i++){
cin >>q;
vector<pi>v;
for(int j = 0; j <q; j++){
cin >> a;
v.pb({tin[a],a});
}
sort(v.begin(),v.end());
for(int j = 0; j < q; j++){
a = v[j].s;
b = v[(j+1)% q].s;
int common = lca(a,b);
val[a]++;
val[b]++;
val[common]-=2;
}
}
dfs1(1,0);
vi ans;
int cnt = 1;
for(pi j: order){
a = min(j.f,j.s);
b = max(j.f,j.s);
// cout <<a<<" " << b << " "<<mp[{a,b}]<< endl;
if(mp[{a,b}]>=k*2) ans.pb(cnt);
cnt++;
}
cout << ans.size() << endl;
for(int i :ans){
cout << i <<" ";
}
cout << endl;
}
/*
*/
