#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
//using namespace __gnu_pbds;
#define LongDepTrai "railway"
#define ll long long
#define int long long
#define ull unsigned long long
#define ld long double
#define ii pair<int,int>
#define iii pair<int,ii>
#define iv pair<ii,ii>
#define pll pair<ll,ll>
#define vi vector<int>
#define vii vector<ii>
#define vll vector<ll>
#define fi first
#define se second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(x) int((x).size())
#define order_set(T) tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>
inline ll add(ll a, ll b, ll mod){ a += b; if(a >= mod) a -= mod; return a; }
inline ll sub(ll a, ll b, ll mod){ a -= b; if(a < 0) a += mod; return a; }
inline ll mul(ll a, ll b, ll mod){ return ( (ll)a * b ) % mod; }
static mt19937_64 rng((unsigned)chrono::steady_clock::now().time_since_epoch().count());
const int N=2e5+9;
const int lg=18;
int n, test, a[N], k,par[N][lg+2], tour[N], timer=0,timer2=0, h[N], kval, dist[N], sz[N], tin[N], tout[N],heavy[N],head[N],pos[N];
//vector<ii> v[N];
vector<int> g[N];
int cnt = 0;
bool ok[N];
struct BIT {
int n;
vector<long long> bit; // 1-indexed
BIT(int n=0) { init(n); }
void init(int _n) {
n = _n;
bit.assign(n+1, 0);
}
// add `val` to index idx (point update on internal BIT)
void addPoint(int idx, long long val) {
for (; idx <= n; idx += idx & -idx) bit[idx] += val;
}
// prefix sum up to idx (inclusive)
long long prefixSum(int idx) const {
long long s = 0;
for (; idx > 0; idx -= idx & -idx) s += bit[idx];
return s;
}
// RANGE UPDATE: add val to all positions in [l, r]
// NOTE: l and r must be 1-indexed and 1 <= l <= r <= n
void rangeAdd(int l, int r, long long val) {
if (l > r) return;
addPoint(l, val);
if (r+1 <= n) addPoint(r+1, -val);
}
// POINT QUERY: get value at position pos (1-indexed)
long long pointQuery(int pos) const {
return prefixSum(pos);
}
} bit;
void dfs(int u, int p) {
tin[u] = ++timer;
for (int e : g[u]) {
int x = e;
if (x == p) continue;
h[x] = h[u] + 1;
//dist[x] = dist[u] + y;
par[x][0] = u;
dfs(x, u);
}
tout[u] = timer;
}
int dfs2(int u,int p){
int mx_sz=0;
int cur_sz=1;
for(int x:g[u]){
if(x==p) continue;
// h[x]=h[u]+1;
// par[x]=u;
int son_sz=dfs2(x,u);
if(son_sz>mx_sz){
mx_sz=son_sz;
heavy[u]=x;
}
cur_sz+=son_sz;
}
return cur_sz;
}
void hld(int u,int h){
head[u]=h;
pos[u]=++timer2;
tour[timer2]=u;
if(heavy[u]) hld(heavy[u],h);
for(int x:g[u]){
if(x!=par[u][0] && x!=heavy[u]){
hld(x,x);
}
}
}
void change(int x,int y){
while(head[x]!=head[y]){
if(h[head[x]]<h[head[y]]) swap(x,y);
// Update(1,pos[head[x]],pos[x],1,n,k);
bit.rangeAdd(pos[head[x]],pos[x],1);
// cout<<tour[pos[head[x]]]<<" "<<x<<"\n";
x=par[head[x]][0];
}
if(h[y]<h[x]) swap(x,y);
// Update(1,pos[x]+1,pos[y],1,n,k);
bit.rangeAdd(pos[x]+1,pos[y],1);
// cout<<tour[pos[x]+1]<<" "<<tour[pos[y]]<<"\n";
}
int lca(int u, int v) {
if (h[u] < h[v]) swap(u, v);
for (int i = lg; i >= 0; i--) {
if ((h[u] - h[v]) >= (1ll << i)) u = par[u][i];
}
if (u == v) return u;
for (int i = lg; i >= 0; i--) {
if (par[u][i] != par[v][i]) {
u = par[u][i];
v = par[v][i];
}
}
return par[u][0];
}
void prelca() {
dfs(1, -1);
for (int j = 1; j <= lg; j++) {
for (int i = 1; i <= n; i++) {
par[i][j] = par[par[i][j-1]][j-1];
}
}
}
bool ss(int x, int y) {
return tin[x] < tin[y];
}
bool inside(int x, int y) {
return (tin[x] <= tin[y] && tin[y] <= tout[x]);
}
int build(vector<int> &ver) {
sort(ver.begin(), ver.end(), ss);
// for(int x:ver) cout<<x<<" ";
// cout<<"\n";
int p = ver.size();
for (int i = 0; i < p-1; i++) {
int z = lca(ver[i], ver[i+1]);
ver.pb(z);
}
sort(ver.begin(), ver.end(), ss);
ver.erase(unique(ver.begin(), ver.end()), ver.end());
vector<int> st;
st.pb(ver[0]);
for (int i = 1; i < ver.size(); i++) {
int u = ver[i];
while(!st.empty() && !inside(st.back(), u)) st.pop_back();
assert(!st.empty());
int last = st.back();
//cout << 0<<" "<<last << " " << u << endl;
change(last,u);
//g[last].pb(u);
st.pb(u);
}
return ver[0];
}
void solve(){
cin >> n >> test>>kval;
bit.init(n+2);
vii ed;
for(int i=1;i<n;i++){
int u,v;
cin>>u>>v;
g[u].pb(v);
g[v].pb(u);
ed.pb({u,v});
//v[u].pb(v);
}
prelca();
dfs2(1,-1);
hld(1,1);
for (int Q = 1; Q <= test; Q++) {
cin >> k;
vector<int> ver(k);
for (int i = 0; i < k; i++) {
cin >> ver[i];
cnt += ver[i];
// cout << "! " << ver[i] << " ";
sz[ver[i]] += ver[i];
}
int goc = build(ver);
// for(int i=2;i<=n;i++){
// cout<<bit.pointQuery(pos[i])<<" ";
// }
// cout<<"\n";
}
vi res;
for(int i=0;i<ed.size();i++){
int u=ed[i].fi;
int v=ed[i].se;
if(h[u]<h[v]) swap(u,v);
if(bit.pointQuery(pos[u])>=kval){
res.pb(i+1);
}
}
cout<<res.size()<<"\n";
for(int x:res) cout<<x<<" ";
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
int t=1;
while(t--){
solve();
}
}
