#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#ifdef DEBUG
#include <time.h>
#endif
#define all(a) (a).begin(), (a).end()
#define rev(a) (a).rbegin(), (a).rend()
#define F first
#define S second
int recur_depth = 0;
#ifdef DEBUG
#define dbg(x) \
{ \
++recur_depth; \
auto x_ = x; \
--recur_depth; \
cerr << string(recur_depth, '\t') << "\e[91m" << __func__ << ":" \
<< __LINE__ << "\t" << #x << " = " << x_ << "\e[39m" << endl; \
}
#else
#define dbg(x)
#endif
using namespace std;
using namespace __gnu_pbds;
typedef pair<int, int> ii;
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> llll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vii;
typedef vector<vii> vvii;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pair<ll, ll>> vll;
typedef vector<vll> vvll;
typedef vector<bool> vb;
template <class type1>
using ordered_set = tree<type1, null_type, less<type1>, rb_tree_tag,
tree_order_statistics_node_update>;
template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<
!is_same<T_container, string>::value,
typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v) {
os << '{';
string sep;
for (const T &x : v)
os << sep << x, sep = ", ";
return os << '}';
}
const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll INF = 1e9;
const ld EPS = 1e-9;
struct Edge {
int u, v, idx;
int cnt_req;
Edge(int u, int v, int idx) : u(u), v(v), idx(idx) {}
};
struct ST {
const int MAXLG = 22;
int n;
vi lg2;
vvii st;
ST(vii &a) : n(a.size()) {
st = vvii(MAXLG, vii(n));
st[0] = a;
for (int j = 1; j < MAXLG; j++)
for (int i = 0; i + (1 << j) <= n; i++)
st[j][i] = min(st[j - 1][i], st[j - 1][i + (1 << (j - 1))]);
lg2 = vi(n + 1);
lg2[1] = 0;
for (int i = 2; i <= n; i++)
lg2[i] = lg2[i / 2] + 1;
}
int query(int l, int r) {
if (l > r)
swap(l, r);
int k = lg2[r - l + 1];
return min(st[k][l], st[k][r - (1 << k) + 1]).second;
}
};
void solve() {
int n, m, k;
cin >> n >> m >> k;
vvii adj(n);
vector<Edge> eds;
for (int i = 0; i < n - 1; i++) {
int u, v;
cin >> u >> v;
u--, v--;
adj[u].push_back({v, i});
adj[v].push_back({u, i});
eds.push_back(Edge(u, v, i));
}
int timer = 0;
vi depth(n), first_occ(n);
vii par(n, {-1, -1}), euler;
function<void(int, int)> f = [&](int u, int p) {
first_occ[u] = euler.size();
euler.push_back({depth[u], u});
for (auto [v, i] : adj[u])
if (v != p) {
depth[v] = depth[u] + 1;
par[v] = {u, i};
f(v, u);
euler.push_back({depth[u], u});
}
};
f(0, -1);
ST st(euler);
vi cnt(n);
for (int i = 0; i < m; i++) {
int s;
cin >> s;
vi us(s);
for (int &x : us)
cin >> x, x--;
int lca = st.query(first_occ[us[0]], first_occ[us[1]]);
cnt[us[0]]++, cnt[us[1]]++;
cnt[lca] -= 2;
for (int i = 2; i < s; i++) {
int u = us[i];
cnt[u]++;
int nxt_lca = st.query(first_occ[u], first_occ[lca]);
if (lca != nxt_lca) {
cnt[lca]++;
cnt[lca = nxt_lca]--;
continue;
}
cnt[st.query(first_occ[u], first_occ[us[i - 1]])]--;
}
}
function<void(int, int)> g = [&](int u, int p) {
for (auto [v, i] : adj[u])
if (v != p) {
g(v, u);
cnt[u] += cnt[v];
}
};
g(0, -1);
assert(cnt[0] == 0);
for (int i = 1; i < n; i++) {
eds[par[i].second].cnt_req = cnt[i];
}
vi res;
for (int i = 0; i < n - 1; i++)
if (eds[i].cnt_req >= k)
res.push_back(i);
cout << res.size() << "\n";
for (int &x : res)
cout << x + 1 << " ";
cout << "\n";
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(NULL);
clock_t start = clock();
int test_cases = 1;
// cin >> test_cases;
while (test_cases--)
solve();
#ifdef DEBUG
cerr << fixed << setprecision(10)
<< "\nTime Taken: " << (double)(clock() - start) / CLOCKS_PER_SEC
<< "s\n";
#endif
return 0;
}
