#include <bits/stdc++.h>
#define lsb(x) (x & (-x))
#define ll long long
#define ull unsigned long long
// 217
// 44
/*const int MOD = (int) 1e9 + 7;
inline int lgput(int a, int b) {
int ans = 1;
while(b > 0) {
if(b & 1) ans = (1LL * ans * a) % MOD;
b >>= 1;
a = (1LL * a * a) % MOD;
}
return ans;
}
inline void mod(int &x) {
if(x >= MOD)
x -= MOD;
}
inline void add(int &x, int y) {
x += y;
mod(x);
}
inline void sub(int &x, int y) {
x += MOD - y;
mod(x);
}
inline void mul(int &x, int y) {
x = (1LL * x * y) % MOD;
}*/
/*int fact[], invfact[];
inline void prec(int n) {
fact[0] = 1;
for(int i = 1; i <= n; i++) {
fact[i] = (1LL * fact[i - 1] * i) % MOD;
}
invfact[n] = lgput(fact[n], MOD - 2);
for(int i = n - 1; i >= 0; i--) {
invfact[i] = (1LL * invfact[i + 1] * (i + 1)) % MOD;
}
}
inline int comb(int n, int k) {
if(n < k) return 0;
return (1LL * fact[n] * (1LL * invfact[k] * invfact[n - k] % MOD)) % MOD;
}*/
using namespace std;
const int MAXN = (int) 1e5;
vector < pair <int, int> > g[MAXN + 1];
int idl[MAXN + 1], idr[MAXN + 1], id;
int rmq[20][2 * MAXN + 1], szr;
int lvl[MAXN + 1], first[MAXN + 1];
void dfs(int nod, int par) {
lvl[nod] = lvl[par] + 1;
rmq[0][++szr] = nod; first[nod] = szr;
idl[nod] = ++id;
for(auto it : g[nod]) {
if(it.first != par) {
dfs(it.first, nod);
rmq[0][++szr] = nod;
}
}
idr[nod] = id;
}
char lg[2 * MAXN + 1];
inline void prec() {
int i;
for(i = 2; i <= szr; i++) {
lg[i] = lg[i >> 1] + 1;
}
for(int bit = 1; (1 << bit) <= szr; bit++) {
for(i = 1; i + (1 << bit) <= szr + 1; i++) {
int a = rmq[bit - 1][i], b = rmq[bit - 1][i + (1 << (bit - 1))];
rmq[bit][i] = (lvl[a] < lvl[b] ? a : b);
}
}
}
inline int get_lca(int x, int y) {
x = first[x], y = first[y];
if(x > y) {
swap(x, y);
}
int bit = lg[y - x + 1];
int a = rmq[bit][x], b = rmq[bit][y - (1 << bit) + 1];
return (lvl[a] < lvl[b] ? a : b);
}
inline bool in(int x, int y) {
return idl[x] <= idl[y] && idr[y] <= idr[x];
}
int sp[MAXN + 1];
vector <int> sol;
void dfs_sp(int nod, int par, int k) {
for(auto it : g[nod]) {
if(it.first != par) {
dfs_sp(it.first, nod, k);
sp[nod] += sp[it.first];
if(sp[it.first] >= k) {
sol.push_back(it.second);
}
}
}
}
int main() {
//ifstream cin("A.in");
//ofstream cout("A.out");
int i, n, m, k;
ios::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
cin >> n >> m >> k;
for(i = 1; i < n; i++) {
int x, y;
cin >> x >> y;
g[x].push_back({y, i});
g[y].push_back({x, i});
}
dfs(1, 0);
prec();
while(m--) {
int sz;
cin >> sz;
vector <int> nodes;
for(i = 0; i < sz; i++) {
int nod;
cin >> nod;
nodes.push_back(nod);
}
sort(nodes.begin(), nodes.end(), [&](const int &x, const int &y) {
return idl[x] < idl[y];
});
for(i = 0; i + 1 < sz; i++) {
nodes.push_back(get_lca(nodes[i], nodes[i + 1]));
}
sort(nodes.begin(), nodes.end(), [&](const int &x, const int &y) {
return idl[x] < idl[y];
});
nodes.resize(unique(nodes.begin(), nodes.end()) - nodes.begin());
stack <int> stk;
for(auto nod : nodes) {
while(stk.size() && !in(stk.top(), nod)) {
stk.pop();
}
if(stk.size()) {
sp[nod]++;
sp[stk.top()]--;
}
stk.push(nod);
}
}
dfs_sp(1, 0, k);
cout << sol.size() << "\n";
sort(sol.begin(), sol.end());
for(auto it : sol) {
cout << it << " ";
}
return 0;
}
