#include <bits/stdc++.h>
using namespace std;
const int N = 100'000 + 10;
int n, m, k;
vector<int> ad[N];
pair<int, int> edge[N];
int f[N][18],st[N], ed[N], it;
void dfs(int u, int p = -1) {
st[u] = ++it;
for (int i = 1; i <= 17; ++i)
f[u][i] = f[f[u][i - 1]][i - 1];
for (const auto& v : ad[u]) {
if (v == p) continue;
f[v][0] = u;
dfs(v, u);
}
ed[u] = it;
}
inline bool anc(int u, int v) { return st[u] <= st[v] && ed[u] >= ed[v]; }
int lca(int u, int v) {
if (anc(u, v)) return u;
if (anc(v, u)) return v;
for (int i = 17; i >= 0; --i)
if (!anc(f[u][i], v)) u = f[u][i];
return f[u][0];
}
int bit[N];
void upd(int i, int x) {
for (; i <= n; i += i & -i) bit[i] += x;
}
int que(int i) {
int ret = 0;
for (; i; i -= i & -i) ret += bit[i];
return ret;
}
int32_t main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n >> m >> k;
for (int i = 1; i < n; ++i) {
int u, v; cin >> u >> v;
edge[i] = {u, v};
ad[u].push_back(v);
ad[v].push_back(u);
}
dfs(f[1][0] = 1);
while (m--) {
int s; cin >> s;
vector<int> vt(s);
for (int i = 0; i < s; ++i) cin >> vt[i];
sort(vt.begin(), vt.end(), [&](const auto& a, const auto& b) {
return st[a] < st[b];
});
vt.push_back(vt[0]);
for (int i = 1; i <= s; ++i) {
int u = vt[i - 1], v = vt[i];
upd(st[lca(u, v)], -2);
upd(st[u], 1);
upd(st[v], 1);
}
}
vector<int> answer;
for (int i = 1; i < n; ++i) {
auto& [u, v] = edge[i];
if (anc(v, u)) swap(u, v);
if (que(ed[v]) - que(st[v] - 1) >= 2 * k) answer.push_back(i);
}
cout << answer.size() << "\n";
for (const auto& x : answer) cout << x << " ";
cout << "\n";
}
