#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define sz(v) (int)v.size()
#define all(v) v.begin(), v.end()
#define filter(v) v.resize(unique(all(v)) - v.begin())
#define dbg(x) "[" #x << " = " << x << "]"
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
template<typename T> bool maximize(T &a, T b) {
if(a < b) return a = b, true;
else return false;
}
template<typename T> bool minimize(T &a, T b) {
if(a > b) return a = b, true;
else return false;
}
template<typename T1, typename T2> T2 rnd(T1 l, T2 r) {
return uniform_int_distribution<T2>(l, r)(rng);
}
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<long long, int> pli;
typedef pair<long long, long long> pll;
const int N = 1e5 + 3;
const int LOG = 20;
int n, m, k;
int eu[N], ev[N];
vector<int> adj[N];
int timer = 0;
int tin[N], tout[N], b[N], dp[N];
int par[N][LOG];
vector<int> edges;
bool isAncestor(int u, int v) {return tin[u] <= tin[v] && tout[v] <= tout[u];}
int getLca(int u, int v) {
if(isAncestor(u, v)) return u;
if(isAncestor(v, u)) return v;
for(int i = LOG - 1; i >= 0; i--)
if(par[u][i] && !isAncestor(par[u][i], v))
u = par[u][i];
return par[u][0];
}
void dfs(int u, int p) {
tin[u] = ++timer;
for(int id : adj[u]) if(id != p) {
int v = eu[id] ^ ev[id] ^ u;
par[v][0] = u;
for(int j = 1; j < LOG; j++) {
par[v][j] = par[par[v][j - 1]][j - 1];
}
dfs(v, id);
}
tout[u] = timer;
}
void dfsDiff(int u, int p) {
dp[u] = b[u];
// cout << dbg(u) << dbg(dp[u]) << endl;
for(int id : adj[u]) if(id != p) {
int v = eu[id] ^ ev[id] ^ u;
dfsDiff(v, id);
dp[u] += dp[v];
if(dp[v] >= 2 * k)
edges.push_back(id);
}
}
void process() {
dfs(1, -1);
while(m--) {
int x; cin >> x;
vector<int> nodes;
while(x--) {
int ver; cin >> ver;
nodes.push_back(ver);
}
sort(all(nodes), [&](int u, int v){
return tin[u] < tin[v];
});
for(int i = 0; i < sz(nodes); i++) {
int j = (i + 1) % sz(nodes);
b[nodes[i]]++;
b[nodes[j]]++;
b[getLca(nodes[i], nodes[j])] -= 2;
// cout << dbg(nodes[i]) << dbg(nodes[j]) << dbg(getLca(nodes[i], nodes[j])) << endl;
}
}
dfsDiff(1, -1);
cout << sz(edges) << endl;
sort(all(edges));
for(int id : edges)
cout << id << " ";
}
void input() {
cin >> n >> m >> k;
for(int i = 1; i < n; i++) {
int u, v; cin >> u >> v;
eu[i] = u;
ev[i] = v;
adj[u].push_back(i);
adj[v].push_back(i);
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
#define task "SUADUONG"
if(fopen(task".INP", "r")) {
freopen(task".INP", "r", stdin);
freopen(task".OUT", "w", stdout);
}
int testcase = 1; // cin >> testcase;
for(int i = 1; i <= testcase; i++) {
input();
process();
}
return 0;
}
