#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define ld long double
#define pb push_back
#define pf push_front
#define vi vector<ll>
#define vii vector<vi>
#define pll pair<ll, ll>
#define vpll vector<pll>
#define all(a) a.begin(), a.end()
#define fi first
#define se second
using namespace std;
const ll mod = 1e9+7;
const ll inf = 2e18;
const ll blocksz = 320;
const ll N = 1e5+8;
int n,m,k;
vector<pair<int,int>> g[N];
int h[N],up[N][20],tin[N],tdfs;
void dfs_pre(int u, int p){
tin[u] = ++tdfs;
for(pair<int,int> ed:g[u]){
int v = ed.fi;
if(v == p) continue;
h[v] = h[u]+1;
up[v][0] = u;
for(int i = 1; i < 20; i++) up[v][i] = up[up[v][i-1]][i-1];
dfs_pre(v,u);
}
}
int lca(int u, int v){
if(h[u] < h[v]) swap(u,v);
int k = h[u]-h[v];
for(int i = 19; i >= 0; i--){
if(k>>i&1) u = up[u][i];
}
if(u == v) return u;
for(int i = 19; i >= 0; i--){
if(up[u][i] != up[v][i]){
u = up[u][i];
v = up[v][i];
}
}
return up[u][0];
}
int f[N];
vector<int> ans;
void dfs(int u, int p, int id){
for(pair<int,int> ed:g[u]){
int v = ed.fi, i = ed.se;
if(v == p) continue;
dfs(v,u,i);
f[u] += f[v];
}
if(f[u] >= 2*k) ans.pb(id);
}
void update(int u, int v){
f[u]++;
f[v]++;
f[lca(u,v)]-=2;
}
void solve(){
cin >> n >> m >> k;
for(int i = 1; i < n; i++){
int u,v;cin >> u >> v;
g[u].pb({v,i});
g[v].pb({u,i});
}
dfs_pre(1,1);
while(m--){
int k;cin >> k;
vector<int> s;
for(int i = 1; i <= k; i++){
int u;cin >> u;
s.pb(u);
}
sort(all(s),[&](int a, int b){
return tin[a] < tin[b];
});
for(int i = 1; i < s.size(); i++){
update(s[i-1],s[i]);
}
update(s.back(),s.front());
}
dfs(1,1,-1);
sort(all(ans));
cout << ans.size() << '\n';
for(int i:ans) cout << i << " ";
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
if (fopen("test.inp", "r")) {
freopen("test.inp", "r", stdin);
freopen("test.out", "w", stdout);
}
ll T = 1;
// cin >> T;
for (ll i = 1; i <= T; i++) {
solve();
cout << '\n';
}
}
