#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
template<class T> void maximize(T& a,const T& b) {if (a < b) a = b;}
template<class T> void minimize(T& a,const T& b) {if (a > b) a = b;}
#define fi first
#define sc second
#define mset(c, x) memset(c, x, sizeof(c))
#define __11HA7_KZ2__ signed main()
int dx[8] = {0, 1, 0,-1, 1, 1,-1,-1};
int dy[8] = {1, 0,-1, 0, 1,-1,-1, 1};
const int N = 1e5;
const int INF = 1e9;
const ll LINF = 1e18;
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
int n, m, k;
vector <pii> adj[N+15];
int timer, tin[N+15], tout[N+15];
int up[20][N+15], sum[N+15], edge_to_node[N+15];
void dfs1(int u, int p) {
tin[u] = ++timer;
up[0][u] = p;
for (int k = 1; k <= 17; k++) {
up[k][u] = up[k-1][up[k-1][u]];
}
for (auto [v, id] : adj[u]) {
if (v != p) {
edge_to_node[id] = v;
dfs1(v, u);
}
}
tout[u] = timer;
}
void dfs2(int u, int p) {
for (auto [v, id] : adj[u]) {
if (v != p) {
dfs2(v, u);
sum[u] += sum[v];
}
}
}
bool isAncestor(int u, int v) {
return tin[u] <= tin[v] and tout[v] <= tout[u];
}
int lca(int u, int v) {
if (isAncestor(u, v)) return u;
if (isAncestor(v, u)) return v;
for (int k = 17; k >= 0; k--) {
if (!isAncestor(up[k][u], v)) {
u = up[k][u];
}
}
return up[0][u];
}
__11HA7_KZ2__
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m >> k;
for (int i = 1; i < n; i++) {
int u, v; cin >> u >> v;
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
timer = 0;
dfs1(1, 1);
for (int i = 1; i <= m; i++) {
int s; cin >> s;
int pre;
for (int j = 1; j <= s; j++) {
int x; cin >> x;
if (j != 1) {
int anc = lca(x, pre);
sum[x]++; sum[pre]++;
sum[anc] -= 2;
}
pre = x;
}
}
dfs2(1, 1);
vector <int> ans;
for (int e = 1; e < n; e++) {
int u = edge_to_node[e];
if (sum[u] >= k) ans.push_back(e);
}
cout << ans.size() << '\n';
for (int x : ans) cout << x <<' ';
}
