#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ll long long
#define all(x) x.begin(), x.end()
#define ins insert
#define pb push_back
#define F first
#define S second
#define bt bitset<5010>
const int N = 1e5 + 100, K = 1610;
const int mod = 998244353;
vector<pair<int, int>>g[N];
vector<int>g1[N];
int tin[N], tout[N], timer, up[N][20], bc[N], head[N], sz[N], pf[N], cnt[N];
int n, m, k;
void init(int v, int p){
sz[v] = 1;
for(auto [to, idx] : g[v]){
if(to == p) continue;
init(to, v);
sz[v] += sz[to];
if(sz[to] > sz[bc[v]]) bc[v] = to;
}
}
void dfs(int v, int p){
tin[v] = ++timer;
up[v][0] = p;
for(int i = 1; i < 20; i++){
up[v][i] = up[up[v][i - 1]][i - 1];
}
if(bc[v]){
head[bc[v]] = head[v];
dfs(bc[v], v);
}
for(auto [to, idx] : g[v]){
if(to == p || to == bc[v]) continue;
head[to] = to;
dfs(to, v);
}
tout[v] = timer;
}
int F(int u, int v){
return tin[u] <= tin[v] && tout[v] <= tout[u];
}
int lca(int u, int v){
if(F(u, v)) return u;
if(F(v, u)) return v;
for(int i = 19; i >= 0; i--){
if(!F(up[u][i], v)) u = up[u][i];
}
return up[u][0];
}
bool cmp(int x, int y){
return tin[x] < tin[y];
}
void dfs2(int v, int p){
for(auto [to, idx] : g[v]){
if(to == p) continue;
dfs2(to, v);
sz[v] += sz[to];
}
}
void solve(){
cin>>n>>m>>k;
for(int i = 1; i <= n - 1; i++){
int u, v;
cin>>u>>v;
g[u].pb({v, i});
g[v].pb({u, i});
}
init(1, 1);
head[1] = 1;
dfs(1, 1);
for(int i = 1; i <= n; i++) sz[i] = 0;
for(int i = 1; i <= m; i++){
vector<int>v;
int z;
cin>>z;
for(int j = 1; j <= z; j++){
int x;
cin>>x;
v.pb(x);
}
sort(all(v), cmp);
v.pb(v[0]);
for(int i = 0; i < z; i++){
sz[v[i]]++;
sz[v[i + 1]]++;
sz[lca(v[i], v[i + 1])] -= 2;
}
}
dfs2(1, 1);
vector<int>ans;
for(int i = 2; i <= n; i++){
if(sz[i] >= 2 * k){
for(auto [to, idx] : g[i]){
if(to == up[i][0]) ans.pb(idx);
}
}
}
cout<<ans.size()<<'\n';
for(auto it : ans) cout<<it<<' ';
}
main(){
ios_base :: sync_with_stdio(false);
cin.tie(nullptr);
int t = 1;
//cin>>t;
while(t--){
solve();
}
}
