//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define enl printf("\n")
#define case(t) printf("Case #%d: ", (t))
#define ni(n) scanf("%d", &(n))
#define nl(n) scanf("%lld", &(n))
#define nai(a, n) for (int i = 0; i < (n); i++) ni(a[i])
#define nal(a, n) for (int i = 0; i < (n); i++) nl(a[i])
#define pri(n) printf("%d\n", (n))
#define prl(n) printf("%lld\n", (n))
#define pii pair<int, int>
#define pil pair<int, long long>
#define pll pair<long long, long long>
#define vii vector<pii>
#define vil vector<pil>
#define vll vector<pll>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef cc_hash_table<int,int,hash<int>> ht;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> oset;
const double pi = acos(-1);
const int MOD = 1e9 + 7;
const int INF = 1e9 + 7;
const int MAXN = 3e5 + 5;
const double eps = 1e-9;
int U[MAXN], V[MAXN], disc[MAXN], cnt[MAXN];
int t = 0, par[17][MAXN], depth[MAXN];
vi adj[MAXN];
void dfs(int u, int p) {
disc[u] = t++;
for (int v: adj[u]) {
if (v == p) continue;
par[0][v] = u;
depth[v] = depth[u] + 1;
dfs(v, u);
}
}
int lca(int u, int v) {
if (depth[u] > depth[v])
swap(u, v);
int d = depth[v] - depth[u];
for (int i = 0; i < 17; i++)
if ((d >> i) & 1)
v = par[i][v];
if (u == v) return u;
for (int i = 16; i > -1; i--)
if (par[i][u] != par[i][v])
u = par[i][u], v = par[i][v];
return par[0][u];
}
void dfs2(int u, int p) {
for (int v: adj[u]) {
if (v == p)
continue;
dfs2(v, u);
cnt[u] += cnt[v];
}
}
int main() {
int n, m, k;
scanf("%d %d %d", &n, &m, &k);
for (int i = 1; i < n; i++) {
scanf("%d %d", &U[i], &V[i]);
U[i]--, V[i]--;
adj[U[i]].pb(V[i]);
adj[V[i]].pb(U[i]);
}
depth[0] = 0;
dfs(0, -1);
for (int i = 1; i < 17; i++)
for (int j = 0; j < n; j++)
par[i][j] = par[i - 1][par[i - 1][j]];
for (int i = 0; i < m; i++) {
vector<int> cur;
int s;
scanf("%d", &s);
for (int j = 0; j < s; j++) {
int u;
scanf("%d", &u);
cur.pb(--u);
}
sort(cur.begin(), cur.end(), [](int u, int v){
return disc[u] < disc[v];
});
for (int j = 0; j < s; j++) {
int l = lca(cur[j], cur[(j+1)%s]);
cnt[l] -= 2;
cnt[cur[j]]++, cnt[cur[(j+1)%s]]++;
}
}
dfs2(0, -1);
vi ans;
for (int i = 1; i < n; i++) {
if (disc[U[i]] < disc[V[i]])
swap(U[i], V[i]);
if (cnt[U[i]] >= 2 * k)
ans.pb(i);
}
printf("%d\n", ans.size());
for (int i: ans)
printf("%d ", i);
printf("\n");
}
