#include <bits/stdc++.h>
using namespace std;
#define int long long int
vector<pair<int, int>> adj[100005];
int succ[100005][20], from[100005], dep[100005], st[100005], en[100005], seg[4*100005], timer = 0;
void update(int n, int l, int r, int i, int v) {
if (l == r) {
seg[n] += v;
} else {
int m = (l+r)/2;
if (l <= i && i <= m) {
update(2*n, l, m, i, v);
} else {
update(2*n+1, m+1, r, i, v);
}
seg[n] = seg[2*n] + seg[2*n+1];
}
}
int query(int n, int l, int r, int a, int b) {
if (b < l || r < a) {
return 0;
} else if (a <= l && r <= b) {
return seg[n];
} else {
int m = (l+r)/2;
return query(2*n, l, m, a, b)+query(2*n+1, m+1, r, a, b);
}
}
void dfs(int i, int p) {
st[i] = timer;
timer++;
for (auto [j, ind] : adj[i]) {
if (j == p) {
from[i] = ind;
continue;
}
dep[j] = dep[i]+1;
succ[j][0] = i;
dfs(j, i);
}
en[i] = timer;
}
void initsucc(int n) {
for (int j = 1; j < 20; j++) {
for (int i = 1; i <= n; i++) {
succ[i][j] = succ[succ[i][j-1]][j-1];
}
}
}
int kthjump(int a, int k) {
for (int j = 0; j < 20; j++) {
if (k & (1 << j)) {
a = succ[a][j];
}
}
return a;
}
int lca(int a, int b) {
if (dep[a] > dep[b]) {
swap(a, b);
}
b = kthjump(b, dep[b]-dep[a]);
if (a == b) {
return a;
}
for (int j = 19; j >= 0; j--) {
if (succ[a][j] != succ[b][j]) {
a = succ[a][j];
b = succ[b][j];
}
}
return succ[a][0];
}
bool cmp(int a, int b) {
return st[a] < st[b];
}
void solve() {
int n, m, k;
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});
}
dfs(1, -1);
initsucc(n);
while(m--) {
int c, l;
cin >> c;
vector<int> a(c);
for (int &x : a) {
cin >> x;
}
sort(a.begin(), a.end(), cmp);
a.push_back(a[0]);
for (int i = 0; i < c; i++) {
l = lca(a[i], a[i+1]);
update(1, 0, n-1, st[a[i]], 1);
update(1, 0, n-1, st[a[i+1]], 1);
update(1, 0, n-1, st[l], -2);
}
}
vector<int> ans;
for (int i = 2; i <= n; i++) {
if (query(1, 0, n-1, st[i], en[i]-1) >= 2*k) {
ans.push_back(from[i]);
}
}
sort(ans.begin(), ans.end());
cout << ans.size() << endl;
for (int i : ans) {
cout << i << " ";
}
cout << endl;
}
int32_t main() {
ios::sync_with_stdio(0);
cin.tie(0);
int t;
t = 1;
while(t--) {
solve();
}
}
