#include <bits/stdc++.h>
using namespace std;
constexpr int N = 1e5, D = 19;
vector<pair<int, int>> g[N];
int ans[N], lz[N], bl[D][N], d[N];
void dfs(int u) {
for (auto &[v, e] : g[u]) {
if (v == bl[0][u]) continue;
bl[0][v] = u;
d[v] = d[u] + 1;
dfs(v);
}
}
void dfs2(int u, int y) {
for (auto &[v, e] : g[u]) {
if (e == y) continue;
dfs2(v, e);
lz[u] += lz[v];
}
ans[y] = lz[u];
}
int lca(int u, int v) {
if (d[u] < d[v]) swap(u, v);
for (int i = D - 1; i >= 0; i--) if (d[u] - d[v] >= 1 << i) u = bl[i][u];
if (u == v) return u;
for (int i = D - 1; i >= 0; i--) if (bl[i][u] != bl[i][v]) u = bl[i][u], v = bl[i][v];
return bl[0][u];
}
signed main() {
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n, q, k;
cin >> n >> q >> k;
for (int i = 1, a, b; i < n; i++) {
cin >> a >> b;
g[--a].push_back({--b, i});
g[b].push_back({a, i});
}
dfs(0);
for (int j = 1; j < D; j++) {
#pragma GCC ivdep
for (int i = 0; i < n; i++) bl[j][i] = bl[j - 1][bl[j - 1][i]];
}
while (q--) {
int s, first, last, x;
cin >> s >> first;
++lz[last = --first];
for (int i = 1; i < s; i++) {
cin >> x;
++lz[--x];
--lz[lca(last, x)];
last = x;
}
--lz[lca(x, first)];
}
dfs2(0, 0);
vector<int> r;
for (int i = 1; i < n; i++) if (ans[i] >= k) r.push_back(i);
cout << r.size() << '\n';
for (int &i : r) cout << i << ' ';
}
