/* Author : Mychecksdead */
#include<bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
typedef long long int ll;
typedef long double ld;
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define PI 3.1415926535
#define pb push_back
#define setp() cout << setprecision(15)
#define all(x) x.begin(), x.end()
#define oset tree<int, null_type,less_equal<int>, rb_tree_tag,tree_order_statistics_node_update>
#define debug(x) cerr << #x << " is " << x << '\n';
const int N = 1e6+100, M = 1e5+10, F = 2147483646, K = 20;
int n, m, k, dep[N], co[N];
vector<pair<int, int>> g[N];
bitset<10005> marked, markede;
vector<pair<int, int>> path;
bool comp(int &a, int &b){
return dep[a] < dep[b];
}
void pre(int v, int p){
dep[v] = dep[p] + 1;
for(auto u: g[v]) if(u.first != p) pre(u.first, v);
}
void dfs(int v, int p){
for(auto u: g[v]){
if(u.first != p){
if(marked[u.first]){
// cout << v << ' ' << u.first << '\n';
int s = path.size() - 1;
while(s >= 0 && !markede[path[s].second]){
co[path[s].second]++;
marked[path[s].first] = 1;
markede[path[s].second] = 1;
// cout << path[s].second << "g\n";
s--;
}
}
path.pb(u);
if(!markede[u.second])
dfs(u.first, v);
if(marked[u.first] && !markede[u.second]){
markede[u.second] = 1, co[u.second]++;
// cout << u.first << ' ' << u.second << "f\n";
}
path.pop_back();
}
}
}
void solve(){
cin >> n >> m >> k;
for(int i = 0; i < n - 1; ++i){
int u, v; cin >> u >> v;
g[u].pb({v, i});
g[v].pb({u, i});
co[i] = 0;
}
dep[1] = 0;
pre(1, 1);
for(int i = 0; i < m; ++i){
marked = markede = 0;
int c; cin >> c;
vector<int> v;
for(int j = 0; j < c; ++j){
int x; cin >> x;
v.pb(x);
marked[x] = 1;
}
for(int p: v) {path.pb({p, n}); dfs(p, p); path.pop_back();}
// cout << '\n';
}
vector<int> ans;
for(int i = 0; i < n - 1; ++i) if(co[i] >= k) ans.pb(i + 1);
cout << ans.size() << '\n';
for(int p: ans) cout << p << ' ';
}
int main(){
cin.tie(0); ios::sync_with_stdio(0);
int T = 1, aa;
// cin >> T;aa=T;
while(T--){
// cout << "Case #" << aa-T << ": ";
solve();
cout << '\n';
}
return 0;
}
