// In the name of God
// Hope is last to die
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define pb push_back
// #define int long long
#define S second
#define F first
#define mp make_pair
#define smax(x, y) (x) = max((x), (y))
#define smin(x, y) (x) = min((x), (y))
#define all(x) (x).begin(), (x).end()
#define len(x) ((int)(x).size())
const int maxn = 1e5 + 5, lg = 20;
const int inf = 1e9 + 7;
int n, m, k, timer, par[maxn][lg], in[maxn], h[maxn], cnt[maxn], id[maxn];
vector<pii> adj[maxn];
void dfs(int v = 1, int p = 0){
in[v] = timer++;
par[v][0] = p;
for(int i = 1; i < lg; i++) par[v][i] = par[par[v][i - 1]][i - 1];
for(auto [u, i]: adj[v]){
if(u == p) continue;
id[i] = u;
h[u] = h[v] + 1;
dfs(u, v);
}
}
int up(int v, int d){
for(int i = 0; i < lg; i++){
if(d & (1ll << i)) v = par[v][i];
}
return v;
}
int lca(int u, int v){
if(h[u] > h[v]) swap(u, v);
v = up(v, h[v] - h[u]);
for(int i = lg - 1; i >= 0; i--){
if(par[u][i] != par[v][i]){
u = par[u][i];
v = par[v][i];
}
}
if(u == v) return u;
return par[v][0];
}
bool cmp(int u, int v){
return in[u] < in[v];
}
void solve(int v, int p){
for(auto [u, i]: adj[v]){
if(p == u) continue;
solve(u, v);
cnt[v] += cnt[u];
}
}
int32_t main()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> m >> k;
for(int i = 0; i < n - 1; i++){
int u, v; cin >> u >> v;
adj[u].pb(mp(v, i));
adj[v].pb(mp(u, i));
}
dfs();
while(m--){
vector<int> vec;
int s; cin >> s;
for(int i = 0; i < s; i++){
int u; cin >> u;
vec.pb(u);
}
sort(all(vec), cmp);
for(int i = 0; i < s; i++){
int l = lca(vec[i], vec[(i + 1) % s]);
cnt[l]--;
cnt[vec[i]]++;
}
}
solve(1, 0);
vector<int> ans;
for(int i = 0; i < n - 1; i++) if(cnt[id[i]] >= k) ans.pb(i);
cout << ans.size() << '\n';
for(auto u: ans) cout << u + 1 << ' ';
cout << '\n';
return 0;
}
