#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e5 + 10, Log = 20;
vector<int> Adj[N];
vector<pair<int, int>> E;
int n, m, k, H[N], P[Log][N], ts, S[N], F[N], O[N];
void PreDFS(int v, int p)
{
S[v] = ++ts;
P[0][v] = p;
for (int i = 1; i < Log; i++)
P[i][v] = P[i - 1][P[i - 1][v]];
for (int u : Adj[v]) if (u != p)
H[u] = H[v] + 1, PreDFS(u, v);
F[v] = ts;
}
int LCA(int u, int v)
{
if (H[u] < H[v])
swap(u, v);
for (int i = 0; i < Log; i++)
if ((H[u] - H[v]) & (1 << i))
u = P[i][u];
if (u == v)
return u;
for (int i = Log - 1; ~i; i--)
if (P[i][u] != P[i][v])
u = P[i][u], v = P[i][v];
return P[0][v];
}
void DFS(int v, int p)
{
for (int u : Adj[v]) if (u != p)
DFS(u, v), O[v] += O[u];
}
signed main()
{
scanf("%d%d%d", &n, &m, &k);
for (int i = 1; i < n; i++)
{
int u, v; scanf("%d%d", &u, &v);
E.push_back({u, v});
Adj[u].push_back(v);
Adj[v].push_back(u);
}
PreDFS(1, 1);
while (m--)
{
int s; scanf("%d", &s);
vector<int> V;
for (int i = 0; i < s; i++)
{
int v;
scanf("%d", &v);
V.push_back(v);
}
sort(V.begin(), V.end(), [&](int a, int b){return S[a] < S[b];});
int high = V[0];
for (int i = 1; i < s; i++)
{
int lca = LCA(V[i - 1], V[i]);
O[lca]--, O[V[i]]++;
if (H[lca] < H[high])
H[high]++, H[lca]--, high = lca;
}
}
DFS(1, 1);
int ans = 0; vector<int> res;
for (int i = 0; i < n - 1; i++)
{
if (S[E[i].first] > S[E[i].second])
if (O[E[i].first] >= k)
ans++, res.push_back(i + 1);
if (S[E[i].first] < S[E[i].second])
if (O[E[i].second] >= k)
ans++, res.push_back(i + 1);
}
printf("%d\n", ans);
for (int x : res)
printf("%d ", x);
return 0;
}
