#include <bits/stdc++.h>
#define int long long
using namespace std;
const long long N = 2e5 + 5;
// const int N = 2e5 + 3;
int a[N];
vector<pair<int, int>> graph[N];
int SP[N][32];
int dist[N];
int mask;
int st[N];
int en[N];
int cnt[N];
vector<int> edges;
int ans = 0;
int now = 1;
int k;
void dfs(int node, int parent)
{
SP[node][0] = parent;
st[node] = now++;
dist[node] = dist[parent] + 1;
for (auto i : graph[node])
{
if (parent != i.first)
dfs(i.first, node);
}
en[node] = now++;
}
int dfs2(int node, int parent)
{
// cnt[node] = 0;
for (auto i : graph[node])
{
if (parent != i.first)
{
cnt[node] += dfs2(i.first, node);
if (cnt[i.first] >= k)
{
edges.push_back(i.second);
}
}
}
ans += cnt[node] >= k && node != 1;
// en[node] = now++;
return cnt[node];
}
void preprocess(int n)
{
for (int p = 1; p < 22; p++)
{
for (int i = 1; i <= n; i++)
{
SP[i][p] = SP[SP[i][p - 1]][p - 1];
}
}
}
void go_up(int &k, int binary)
{
for (int i = 0; i < 20; i++)
{
mask = 1LL << i;
if ((binary & mask) != 0)
{
k = SP[k][i];
}
}
}
int same_at_height(int u, int v)
{
if (u == v)
return v;
for (int i = 19; i >= 0; i--)
{
if (SP[u][i] != SP[v][i])
{
u = SP[u][i];
v = SP[v][i];
}
}
return SP[u][0];
}
int lca(int u, int v)
{
if (dist[u] > dist[v])
swap(u, v);
int diff = dist[v] - dist[u];
go_up(v, diff);
if (u == v)
return u;
return same_at_height(u, v);
}
void solve()
{
int n, m;
cin >> n >> m >> k;
// dist[0] = 1;
int u, v;
for (int i = 0; i < n - 1; i++)
{
cin >> u >> v;
graph[u].emplace_back(v, i + 1);
graph[v].emplace_back(u, i + 1);
}
dfs(1, 0);
preprocess(n + 1);
int nn;
for (int i = 0; i < m; i++)
{
cin >> nn;
vector<pair<int, int>> ls;
for (int i = 0; i < nn; i++)
{
cin >> u;
ls.push_back({st[u], u});
}
sort(ls.begin(), ls.end());
for (int i = 0; i < nn - 1; i++)
{
int x = ls[i].second;
int y = ls[i + 1].second;
int lc = lca(x, y);
ls.push_back({st[lc], lc});
}
sort(ls.begin(), ls.end());
ls.erase(unique(ls.begin(), ls.end()), ls.end());
vector<int> stac;
for (auto &p : ls)
{
int x = p.second;
while (!stac.empty() and en[stac.back()] < st[x])
stac.pop_back();
if (!stac.empty())
{
cnt[stac.back()]--;
cnt[x]++;
}
stac.push_back(x);
}
}
dfs2(1, 0);
cout << edges.size() << endl;
sort(edges.begin(), edges.end());
for (auto i : edges)
{
cout << i << ' ';
}
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
int t = 1;
// cin >> t;
for (int i = 1; i <= t; i++)
{
// cout << "Case #" << i << ':' << ' ';
solve();
cout << endl;
}
return 0;
}
