#include <bits/stdc++.h>
#define int long long
#define fi first
#define se second
#define sz(a) (int)((a).size())
#define all(a) (a).begin(), (a).end()
#define lsb(x) (x & (-x))
#define vi vector<int>
#define YES { cout << "YES" << endl; return; }
#define NO { cout << "NO" << endl; return; }
using ll = long long;
using pii = std::pair<int, int>;
const int NMAX = 1e5;
using namespace std;
template<class T>
struct RMQ {
vector<vector<T>> rmq;
T kInf = numeric_limits<T>::max();
void build(const vector<T>& V) {
int n = (int) V.size(), on = 1, dep = 1;
while (on < n) on *= 2, ++dep;
rmq.assign(dep, V);
for (int i = 0; i < dep - 1; i++) {
for (int j = 0; j < n; j++) {
int nj = min(n - 1, j + (1 << i));
rmq[i + 1][j] = min(rmq[i][j], rmq[i][nj]);
}
}
}
T query(int a, int b) {
if (b <= a) return kInf;
int dep = 31 - __builtin_clz(b - a);
return min(rmq[dep][a], rmq[dep][b - (1 << dep)]);
}
};
struct LCA {
vector<int> enter, depth, ex;
vector<vector<int>> G;
vector<pair<int, int>> linear;
RMQ<pair<int, int>> rmq;
int timer = 0;
LCA() {}
LCA(int n) : enter(n, -1), depth(n), ex(n), G(n), linear(2 * n) {}
void dfs(int v, int d) {
linear[timer] = { d, v };
enter[v] = timer++;
depth[v] = d;
for (int to : G[v]) {
if (enter[to] == -1) {
dfs(to, d + 1);
linear[timer++] = { d, v };
}
}
ex[v] = timer;
}
void add_edge(int a, int b) {
G[a].push_back(b);
G[b].push_back(a);
}
void build(int root) {
fill(enter.begin(), enter.end(), -1);
timer = 0;
dfs(root, 0);
rmq.build(linear);
}
int query(int a, int b) {
a = enter[a];
b = enter[b];
return rmq.query(min(a, b), max(a, b) + 1).second;
}
int dist(int a, int b) {
int c = query(a, b);
return depth[a] + depth[b] - 2 * depth[c];
}
};
LCA lca;
vector<int>T[NMAX + 5];
vector<int>ans;
map<pii, int>mp;
int a[NMAX + 5], in[NMAX + 5], mars[NMAX + 5], n, m, k, timer = 0;
void dfs_ord(int nod, int p = -1) {
in[nod] = timer++;
for (auto &son : T[nod]) {
if (son == p)continue;
dfs_ord(son, nod);
}
}
int dfs_mars(int nod, int p = -1) {
int sum = mars[nod];
for (auto &son : T[nod]) {
if (son == p) continue;
int offset = dfs_mars(son, nod);
if (offset >= 2 * k)
ans.push_back(mp[{nod, son}]);
sum += offset;
}
return sum;
}
signed main() {
cin.tie(nullptr)->sync_with_stdio(false);
cin >> n >> m >> k;
lca = LCA(n + 5);
for (int i = 1, u, v; i <= n - 1; ++i) {
cin >> u >> v;
T[u].push_back(v);
T[v].push_back(u);
lca.add_edge(u, v);
mp[{u, v}] = i;
mp[{v, u}] = i;
}
lca.build(1);
dfs_ord(1);
for (int i = 1, k; i <= m; ++i) {
cin >> k;
for (int j = 1; j <= k; ++j)
cin >> a[j];
sort(a + 1, a + k + 1, [](auto& a, auto& b) {
return in[a] < in[b];
});
a[k + 1] = a[1];
for (int j = 1; j <= k; ++j) {
++mars[a[j]];
++mars[a[j + 1]];
mars[lca.query(a[j], a[j + 1])] -= 2;
}
}
dfs_mars(1);
sort(all(ans));
cout << sz(ans) << '\n';
for (auto &it : ans)
cout << it << " \n"[it == ans.back()];
return 0;
}
