#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
const int maxn = 1e5 + 5, logn = 17;
int n, m, k, l[logn][maxn], tin[maxn], d[maxn], sum[maxn], id[maxn], timer = 0;
vector<pair<int, int> > g[maxn];
void dfs1(int u)
{
tin[u] = timer++;
for (int i = 1; i < logn; i++) l[i][u] = l[i-1][l[i-1][u]];
for (pair<int, int> v : g[u])
{
if (v.first == l[0][u]) continue;
l[0][v.first] = u, d[v.first] = d[u] + 1;
id[v.first] = v.second;
dfs1(v.first);
}
}
int lca(int a, int b)
{
if (d[a] < d[b]) swap(a, b);
for (int i = logn-1; i >= 0; i--) if (d[l[i][a]] >= d[b]) a = l[i][a];
if (a==b) return a;
for (int i = logn-1; i >= 0; i--) if (l[i][a] ^ l[i][b]) a = l[i][a], b = l[i][b];
return l[0][a];
}
vector<int> ans;
void dfs2(int u)
{
for (pair<int, int> v : g[u]) if (v.first ^ l[0][u])
{
dfs2(v.first);
sum[u] += sum[v.first];
}
if (sum[u] >= k) ans.push_back(id[u]);
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n >> m >> k;
for (int i = 0, a, b; i < n-1; i++)
{
cin >> a >> b, a--, b--;
g[a].push_back({b, i+1}), g[b].push_back({a, i+1});
}
dfs1(0);
for (int i = 0; i < m; i++)
{
int s; cin >> s;
vector<pair<int, int> > v(s);
for (int j = 0; j < s; j++) cin >> v[j].second, sum[--v[j].second]++, v[j].first = tin[v[j].second];
sort(v.begin(), v.end());
int root = v[0].second;
for (int j = 1; j < s; j++)
{
int l = lca(v[j-1].second, v[j].second);
root = lca(root, v[j].second);
sum[l]--;
}
sum[root]--;
}
dfs2(0);
cout << ans.size() << "\n";
sort(ans.begin(), ans.end());
for (int i : ans) cout << i << " ";
cout << "\n";
return 0;
}
