#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(x) begin(x), end(x)
#define sz(x) (int)x.size()
#define pb push_back
struct LCA{
int n;
vector<vector<int>> adj, up;
vector<int> depth;
LCA(int _n){
n = _n;
up.resize(n+1);
for(int i=0; i<=n; i++){
up[i].resize(20, 0);
}
adj.resize(n+1);
depth.resize(n+1);
}
void ae(int a, int b){
adj[a].pb(b);
adj[b].pb(a);
}
void dfs(int s, int p){
depth[s] = depth[p]+1;
up[s][0] = p;
for(auto u: adj[s]){
if(u == p) continue;
dfs(u, s);
}
}
void init(){
depth[0] = 0;
dfs(1, 0);
for(int j=1; j<20; j++){
for(int i=1; i<=n; i++){
up[i][j] = up[up[i][j-1]][j-1];
}
}
}
int jump(int x, int d){
for(int i=0; i<20; i++){
if(d & (1<<i)) x = up[x][i];
}
return x;
}
int lca(int a, int b){
if(depth[a] < depth[b]) swap(a, b);
a = jump(a, depth[a]-depth[b]);
if(a == b) return a;
for(int i=19; i>=0; i--){
if(up[a][i] != up[b][i]){
a = up[a][i];
b = up[b][i];
}
}
return up[a][0];
}
int dist(int a, int b){
int c = lca(a, b);
int d = depth[a]+depth[b]-2*depth[c];
return d;
}
};
const int maxn = 100001;
vector<int> adj[maxn];
set<int> add[maxn], rem[maxn];
int num[maxn];
void dfs(int s, int p){
for(auto u: adj[s]){
if(u == p) continue;
dfs(u, s);
if(sz(add[u]) > sz(add[s])) swap(add[u], add[s]);
for(auto e: add[u]) add[s].insert(e);
}
num[s] = sz(add[s]);
for(auto e: rem[s]) add[s].erase(e);
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
int n, m, k; cin >> n >> m >> k;
vector<pair<int, int>> edges(n-1);
LCA L(n);
for(int i=0; i<n-1; i++){
int a, b; cin >> a >> b;
L.ae(a, b);
adj[a].pb(b); adj[b].pb(a);
edges[i] = {a, b};
}
L.init();
for(int j=1; j<=m; j++){
int s; cin >> s;
vector<int> v(s);
for(int i=0; i<s; i++) cin >> v[i];
int c = L.lca(v[0], v[1]);
for(int i=2; i<s; i++){
c = L.lca(c, v[i]);
}
add[c].insert(j);
for(auto e: v){
while(e != c){
add[e].insert(j);
e = L.up[e][0];
}
}
}
for(int i=1; i<=n; i++) num[i] = sz(add[i]);
vector<int> ans;
for(int i=0; i<n-1; i++){
auto &[a, b] = edges[i];
if(num[a] >= k and num[b] >= k) ans.pb(i+1);
}
cout << sz(ans) << "\n";
for(auto e: ans) cout << e << ' ';
}
