#include <bits/stdc++.h>
using namespace std;
#define pii pair<int, int>
#define fi first
#define se second
const int MX = 2e5 + 10;
const int LG = 19;
struct segtree{
int st[MX << 1];
void upd(int l, int r, int v){
for(l += MX, r += MX + 1; l < r; l >>= 1, r >>= 1){
if(l & 1) st[l++] += v;
if(r & 1) st[--r] += v;
}
}
int que(int p){
int res = 0;
for(p += MX; p > 0; p >>= 1) res += st[p];
return res;
}
} S;
struct segversion{
int st[MX << 1];
void upd(int l, int r, int v){
for(l += MX, r += MX + 1; l < r; l >>= 1, r >>= 1){
if(l & 1) st[l++] = v;
if(r & 1) st[--r] = v;
}
}
int que(int p){
int res = 0;
for(p += MX; p > 0; p >>= 1) res = max(res, st[p]);
return res;
}
} T;
vector<int> adj[MX];
int N, M, K, par[MX], head[MX], sp[MX][LG];
int sz[MX], dep[MX], in[MX], out[MX], tim = 0;
void dfs(int u, int v){
if(v != 0) adj[u].erase(find(adj[u].begin(), adj[u].end(), v));
sz[u] = 1; dep[u] = dep[v] + 1;
sp[u][0] = par[u] = v;
for(int i = 1; i < LG; i++) sp[u][i] = sp[sp[u][i - 1]][i - 1];
for(int& nxt : adj[u]){
dfs(nxt, u);
sz[u] += sz[nxt];
if(sz[nxt] > sz[adj[u][0]]) swap(nxt, adj[u][0]);
}
}
void dfs2(int u){
in[u] = ++tim;
for(int nxt : adj[u]){
if(nxt == adj[u][0]) head[nxt] = head[u];
else head[nxt] = nxt;
dfs2(nxt);
}
out[u] = tim;
}
void init(){
dfs(1, 0);
head[1] = 1;
dfs2(1);
}
int lca(int u, int v){
if(dep[u] > dep[v]) swap(u, v);
int df = dep[v] - dep[u];
for(int j = 0; j < LG; j++){
if(df >> j & 1) v = sp[v][j];
}
if(u == v) return u;
for(int j = LG - 1; j >= 0; j--){
if(sp[u][j] != sp[v][j]){
u = sp[u][j];
v = sp[v][j];
}
}
return sp[u][0];
}
void upd(int u, int v, int val){
for(; head[u] != head[v]; v = par[head[v]]){
if(dep[u] > dep[v]) swap(u, v);
S.upd(in[head[v]], in[v], 1);
T.upd(in[head[v]], in[v], val);
}
if(dep[u] > dep[v]) swap(u, v);
S.upd(in[u], in[v], 1);
T.upd(in[u], in[v], val);
}
vector<pair<pii, int>> edges;
int find_rep(int u, int root, int ver){ // find ancestor of u that is lower than root and off
for(int i = LG - 1; i >= 0; i--){
if(dep[sp[u][i]] > dep[root] && T.que(in[sp[u][i]]) != ver) u = sp[u][i];
}
return u;
}
int idx_edge[MX];
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> N >> M >> K;
for(int i = 1; i < N; i++){
int u, v; cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
edges.push_back({{u, v}, i});
}
init();
for(auto edge : edges){
if(dep[edge.fi.fi] > dep[edge.fi.se]) idx_edge[edge.fi.fi] = edge.se;
else if(dep[edge.fi.fi] < dep[edge.fi.se]) idx_edge[edge.fi.se] = edge.se;
}
for(int i = 1; i <= M; i++){
int s; cin >> s;
vector<int> curr;
int root = -1;
for(int j = 1; j <= s; j++){
int nd; cin >> nd;
if(root == -1) root = nd;
else root = lca(root, nd);
curr.push_back(nd);
}
T.upd(in[root], in[root], i);
for(int x : curr){
if(x == root || T.que(in[x]) == i) continue;
int nd = find_rep(x, root, i);
upd(x, nd, i);
}
}
vector<int> answ;
for(int i = 1; i <= N; i++){
if(S.que(in[i]) >= K) answ.push_back(idx_edge[i]);
}
sort(answ.begin(), answ.end());
cout << answ.size() << '\n';
for(int x : answ) cout << x << " ";
cout << '\n';
}
