#include <bits/stdc++.h>
#define ll long long int
#define f first
#define s second
#define pii pair<int,int>
#define pll pair<long long,long long>
#define pcc pair<char,char>
#define pbb pair<bool,bool>
#define PB push_back
#define PF push_front
#define MOD 1000000007
#define intxt freopen("input.txt","r",stdin)
#define outtxt freopen("output.txt","w",stdout)
using namespace std;
const int MAXN = 1e5 + 10;
ll n ,q ,k ,q1 ,q2 ,qq ,x = 1;
ll par[MAXN][20] ,h[MAXN] ,st[MAXN];
ll change[MAXN] ,ans[MAXN];
vector <pii> adj[MAXN];
vector <int> isvalid;
inline void dfs(int v , int p = 0) {
st[v] = x;
x++;
for(auto u : adj[v]) {
if(u.f == p) {
continue;
}
h[u.f] = h[v] + 1;
par[u.f][0] = v;
dfs(u.f , v);
}
}
inline ll bridge_cost(int v , int p = 0) {
int cnt = change[v];
for(auto u : adj[v]) {
if(u.f == p) {
continue;
}
ans[u.s] = bridge_cost(u.f ,v);
cnt += ans[u.s];
if(ans[u.s] >= (2 * k)) {
isvalid.PB(u.s);
}
}
return cnt;
}
ll LCA(int v , int u) {
if(h[u] < h[v]) {
swap(u ,v);
}
for(int i = 17 ; i >= 0 ; i--) {
if(h[par[u][i]] >= h[v]) {
u = par[u][i];
}
}
if(u == v) {
return v;
}
for(int i = 17 ; i >= 0 ; i--) {
if(par[u][i] != par[v][i]) {
u = par[u][i];
v = par[v][i];
}
}
return par[v][0];
}
bool cmp(const int u , const int v) {
return st[v] < st[u];
}
int main() {
ios_base::sync_with_stdio(0);
cin >> n >> q >> k;
for(int i = 1 ; i < n ; i++) {
cin >> q1 >> q2;
adj[q1].PB(make_pair(q2 , i));
adj[q2].PB(make_pair(q1 , i));
}
dfs(1);
for(int j = 1 ; j <= 17 ; j++) {
for(int i = 1 ; i <= n ; i++) {
par[i][j] = par[par[i][j - 1]][j - 1];
}
}
while(q--) {
cin >> qq;
int a[qq + 10];
for(int i = 1 ; i <= qq ; i++) {
cin >> a[i];
}
sort(a + 1 ,a + qq + 1 ,cmp);
for(int i = 1 ; i < qq ; i++) {
change[LCA(a[i] ,a[i + 1])] -= 2;
change[a[i]]++;
change[a[i + 1]]++;
}
change[LCA(a[qq] ,a[1])] -= 2;
change[a[qq]]++;
change[a[1]]++;
}
bridge_cost(1);
sort(isvalid.begin() ,isvalid.end());
cout << isvalid.size() << endl;
for(auto x : isvalid) {
cout << x << " ";
}
}
// Hello
