#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ff first
#define ss second
#define all(a) a.begin(), a.end()
const int N = 2e5;
const int LOG = 20;
int up[N+1][LOG+1], depth[N+1], sub[N+1];
int bigchild[N+1], chain[N+1], Pos[N+1];
int n, m, k;
vector< pair<int, int> > edge;
vector<int> ans, g[N+1], ministr[N+1], tins[N+1];
int tin[N+1], tout[N+1], T, position;
void dfs(int v, int p){
tin[v] = ++T;
up[v][0] = p;
for(int j = 1;j < LOG; j++) up[v][j] = up[up[v][j-1]][j-1];
sub[v] = 1;
int big=-1;
for(auto to : g[v]){
if(to != p){
depth[to] = depth[v]+1;
dfs(to, v);
sub[v]+= sub[to];
if(big == -1 or sub[big] < sub[to]){
big = to;
}
}
}
tout[v] = ++T;
bigchild[v] = big;
}
int upper(int v, int p){
return (tin[p] <= tin[v] and tout[v] <= tout[p]);
}
void decompose(int v, int head){
Pos[v] = ++position;
chain[v] = head;
if(bigchild[v] != -1){
decompose(bigchild[v], head);
}
for(auto to : g[v]){
if(to == up[v][0] or to == bigchild[v]) continue;
decompose(to, to);
}
}
int t[4*N], lazy[4*N];
void push(int v, int vl, int vr){
if(lazy[v] == 0) return;
t[v]+= (lazy[v] * (vr-vl+1));
if(vl != vr){
lazy[v<<1]+= lazy[v];
lazy[v<<1|1]+= lazy[v];
}
lazy[v] = 0;
}
void add(int l, int r, int x, int v, int vl, int vr){
push(v, vl, vr);
if(l > vr or vl > r) return;
if(l <= vl and r >= vr){
lazy[v]+= x;
push(v, vl, vr);
return;
}
int mid = (vl + vr)>>1;
add(l, r, x, v<<1, vl, mid);
add(l, r, x, v<<1|1, mid+1, vr);
t[v] = t[v<<1] + t[v<<1|1];
}
int get(int pos, int v, int vl, int vr){
push(v, vl, vr);
if(vl == vr) return t[v];
int mid = (vl + vr)>>1;
if(mid >= pos) return get(pos, v<<1, vl, mid);
else return get(pos, v<<1|1, mid+1, vr);
}
void query(int a, int b, int x){
for(; chain[a] != chain[b]; ){
if(depth[b] < depth[a]) swap(a, b);
add(min(Pos[b], Pos[chain[b]]), max(Pos[b], Pos[chain[b]]), x, 1, 1, n);
b = up[chain[b]][0];
}
if(depth[b] < depth[a]) swap(a, b);
add(min(Pos[a], Pos[b]), max(Pos[a], Pos[b]), x, 1, 1, n);
}
int lca(int a, int b){
if(depth[a] > depth[b]) swap(a, b);
if(upper(a, b)) return a;
int k =depth[b]-depth[a];
for(int i = 0;i < LOG; i++){
if(k&(1LL<<i)){
b = up[b][i];
}
}
if(a == b) return a;
for(int i = LOG-1; i >= 0; i--){
if(up[a][i] != up[b][i]){
a = up[a][i], b = up[b][i];
}
}
return up[a][0];
}
main(){
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> n >> m >> k;
for(int i = 1;i < n; i++){
int a, b; cin >> a >> b;
edge.push_back({a, b});
g[a].push_back(b);
g[b].push_back(a);
}
dfs(1, 1);
decompose(1, 1);
for(int i = 1;i <= m; i++){
int sz; cin >> sz;
for(int j = 0;j < sz; j++){
int idx; cin >> idx;
ministr[i].push_back(idx);
}
}
vector<int> cnt(n, 0);
vector<int> ans;
for(int i = 1;i <= m; i++){
sort(all(ministr[i]), [&](int A, int B){
return tin[A] < tin[B];
});
for(int j = 0;j < ministr[i].size(); j++){
int a = ministr[i][j], b = ministr[i][(j + 1) % (int)ministr[i].size()];
// cout << a << ' ' << b << '\n';
int lc = lca(a, b);
query(a, lc, 1);
query(b, lc, 1);
add(Pos[lc], Pos[lc], -2, 1, 1, n);
}
// cout << '\n' << '\n';
}
for(int i = 0;i < n-1; i++){
int a = edge[i].ff, b = edge[i].ss;
if(tin[a] > tin[b]) swap(a, b);
cnt[i] = get(Pos[b], 1, 1, n);
if(cnt[i] >=2* k){
ans.push_back(i + 1);
}
}
sort(all(ans));
cout << ans.size() << '\n';
for(int x : ans) cout << x << ' ';
return 0;
}
