// Source: https://oj.uz/problem/view/BOI17_railway
//
#include "bits/stdc++.h"
using namespace std;
#define s second
#define f first
#define pb push_back
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<pii> vpii;
typedef vector<int> vi;
#define FOR(i, a, b) for (int i = (a); i<b; i++)
const int N = 1e5 + 10;
vi adj[N];
int tin[N];
int tout[N];
int dep[N];
int bit[N];
int query_pref(int ind) {
int ret = 0;
for (; ind >= 0; ind = (ind & (ind + 1)) - 1)
ret += bit[ind];
return ret;
}
int query(int ind1, int ind2) {
return query_pref(ind2 - 1) - query_pref(ind1-1);
}
void update(int ind, int val) {
for (; ind < N; ind = ind | (ind + 1))
bit[ind] += val;
}
int lift[N][20];
int timer = 0;
void dfs(int cur, int p) {
tin[cur]=timer++;
lift[cur][0]=p;
dep[cur] = dep[p] + 1;
for (auto val: adj[cur]) if (val != p) dfs(val, cur);
tout[cur]=timer;
}
int jmp(int a, int d) {
// cout << ' ' << a << d << endl;
for (int i = 19; i>= 0; i--) if ((1 << i) & d) a = lift[a][i];
// cout << a << endl;
return a;
}
int LCA(int a, int b) {
if (dep[b] > dep[a]) swap(a, b); // a is lower
// cout << a << b << dep[a] << dep[b] << endl;
a = jmp(a, dep[a]-dep[b]);
// cout << a << b << endl;
if (a==b)return a;
for (int i = 19; i>= 0; i--)
if (lift[a][i] != lift[b][i]) {
a = lift[a][i];
a = lift[b][i];
}
// cout << a << b << endl;
assert(lift[a][0] == lift[b][0]);
return lift[a][0];
}
pii edges[N];
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m, k;
cin >> n >> m >> k;
FOR(i, 0, n-1) {
int a, b;
cin >> a >> b;
adj[a].pb(b);
adj[b].pb(a);
edges[i]={a, b};
}
dfs(1, 0);
FOR(j, 1, 20) FOR(i, 1, n + 1) lift[i][j] = lift[lift[i][j-1]][j-1];
int s;
FOR(i, 0, m) {
cin >> s;
int cur[s+1];
FOR(j, 0, s)
cin >> cur[j];
sort(cur, cur + s, [&](int a, int b) {return tin[a] < tin[b]; });
cur[s] = cur[0];
FOR(i, 0, s) {
int lca = LCA(cur[i], cur[i + 1]);
// cout << cur[i] << cur[i + 1] << lca << endl;
update(tin[lca], -2);
update(tin[cur[i]], 1);
update(tin[cur[i + 1]], 1);
}
}
vi ans;
FOR(i, 0, n - 1) {
if (dep[edges[i].f] < dep[edges[i].s]) swap(edges[i].f, edges[i].s);
if (query(tin[edges[i].f], tout[edges[i].f]) >= 2 * k) ans.pb(i + 1);
}
cout << ans.size() << endl;
for (auto val: ans) cout << val << ' ';
cout << endl;
}
