#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<ll, ll>
#define fi first
#define sec second
#define ld long double
const ll N = 1e5;
const ll INF = 4e18;
const ll MOD = 998244353;
vector<pii> adj[N + 5];
ll tin[N + 5], tout[N + 5], p[N + 5], dist[N + 5];
ll dp[N + 5], edges[N + 5];
ll t = 0;
void dfs(ll idx, ll par){
if(idx != 1) p[idx] = par;
tin[idx] = ++t;
for(auto [i, j] : adj[idx]){
if(i != par){
dist[i] = dist[idx] + 1;
dfs(i, idx);
}
}
tout[idx] = t;
}
void dfs2(ll idx, ll par){
for(auto [i, j] : adj[idx]){
if(i != par){
dfs2(i, idx);
dp[idx] += dp[i];
edges[j] = dp[i];
}
}
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int tc = 1;
// cin >> tc;
for(;tc--;){
ll n, m, k; cin >> n >> m >> k;
for(int i = 1; i <= n - 1; i++){
ll u, v; cin >> u >> v;
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
dfs(1, -1);
vector<vector<ll>> up(n + 5, vector<ll>(30));
for(int LOG = 0; LOG < 30; LOG++){
for(int i = 1; i <= n; i++){
if(LOG == 0) up[i][LOG] = p[i];
else up[i][LOG] = up[up[i][LOG - 1]][LOG - 1];
}
}
auto binlift = [&](ll idx, ll len){
for(int i = 0; i < 30; i++){
if(len & (1LL << i)){
idx = up[idx][i];
}
}
return idx;
};
auto get_lca = [&](ll a, ll b){
if(dist[a] < dist[b]) swap(a, b);
a = binlift(a, dist[a] - dist[b]);
if(a == b) return a;
for(int i = 29; i >= 0; --i){
if(up[a][i] != up[b][i]){
a = up[a][i], b = up[b][i];
}
}
return up[a][0];
};
for(int i = 1; i <= m; i++){
ll s; cin >> s;
vector<ll> v;
for(int j = 1; j <= s; j++){
ll x; cin >> x;
v.push_back(x);
}
sort(v.begin(), v.end(), [&](ll a, ll b){
return tin[a] < tin[b];
});
v.push_back(v[0]);
// simulate dfs, satu edge divisit pas 2x
for(int i = 1; i < v.size(); i++){
ll LCA = get_lca(v[i - 1], v[i]);
dp[v[i - 1]]++, dp[v[i]]++;
dp[LCA] -= 2;
}
}
dfs2(1, -1);
vector<ll> ans;
for(int i = 1; i <= n - 1; i++){
if(edges[i] / 2 >= k){
ans.push_back(i);
}
}
cout << ans.size() << "\n";
for(auto i : ans) cout << i << " ";
cout << "\n";
}
}
/*
*/
