#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template <class T> using oset=tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
//- insert(x),erase(x)
//- find_by_order(k): return iterator to the k-th smallest element
//- order_of_key(x): the number of elements that are strictly smaller
#define ll long long
#define ld long double
#define ar array
#define vt vector
#define pb push_back
#define bit(i, x) ((x>>i)&1ULL)
#define pf push_front
#define all(v) v.begin(), v.end()
#define lla(v) v.rbegin(), v.rend()
/*mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll get_rand(ll l, ll r) {
return uniform_int_distribution<ll> (l, r)(rng);
}*/
const int mxN=1e5+5;
const int LG=21;
int n, m, k, timer=0;
int tin[mxN], tout[mxN], bit[mxN], depth[mxN], up[mxN][LG], edge[mxN];
vt<pair<int, int>> adj[mxN];
void dfs(int u=1) {
tin[u]=++timer;
for(pair<int, int> ele: adj[u]) {
int v=ele.first;
int ii=ele.second;
if(v==up[u][0]) {
continue;
}
up[v][0]=u;
depth[v]=depth[u]+1;
edge[v]=ii;
for(int i=1; i<LG; ++i) {
up[v][i]=up[up[v][i-1]][i-1];
}
dfs(v);
}
tout[u]=timer;
}
int lca(int u, int v) {
if(depth[u]!=depth[v]) {
if(depth[u]<depth[v]) {
swap(u, v);
}
int k=depth[u]-depth[v];
for(int i=LG-1; i>=0; --i) {
if(bit(i, k)) {
u=up[u][i];
}
}
}
if(u==v) {
return u;
}
for(int i=LG-1; i>=0; --i) {
if(up[u][i]!=up[v][i]) {
u=up[u][i];
v=up[v][i];
}
}
return up[u][0];
}
void upd(int idx, int val) {
for(; idx<=mxN; idx+=(idx&(-idx))) {
bit[idx]+=val;
}
}
int qury(int l, int r) {
int res=0;
for(; r>0; r-=(r&(-r))) {
res+=bit[r];
}
if(l-1==0) {
return res;
}
for(--l; l>0; l-=(l&(-l))) {
res-=bit[l];
}
return res;
}
void solve() {
//solve here
cin >> n >> m >> k;
for(int i=1; i<=n-1; ++i) {
int u, v;
cin >> u >> v;
adj[u].pb({v, i});
adj[v].pb({u, i});
}
dfs();
for(int ii=0; ii<m; ++ii) {
int sz;
cin >> sz;
vt<int> vec;
for(int i=0; i<sz; ++i) {
int aa;
cin >> aa;
vec.pb(aa);
}
sort(all(vec), [&](int A, int B) {
return tin[A]<tin[B];
});
for(int i=1; i<sz; ++i) {
int l=lca(vec[i-1], vec[i]);
upd(tin[vec[i-1]], 1);
upd(tin[vec[i]], 1);
upd(tin[l], -2);
}
int l=lca(vec[sz-1], vec[0]);
upd(tin[vec[sz-1]], 1);
upd(tin[vec[0]], 1);
upd(tin[l], -2);
}
vt<int> ans;
for(int i=2; i<=n; ++i) {
if(qury(tin[i], tout[i])>=2*k) {
ans.pb(edge[i]);
}
}
sort(all(ans));
cout << ans.size() << "\n";
for(auto& ele: ans) {
cout << ele << " ";
}
cout << "\n";
}
signed main() {
ios::sync_with_stdio(0);
cin.tie(0);
//freopen("template.inp", "r", stdin);
//freopen("template.out", "w", stdout);
int TC=1;
//cin >> TC;
while(TC--) {
solve();
}
}
