#include <bits/stdc++.h>
using namespace std;
const int nx=1e5+5, kx=17;
int n, m, k, pa[nx][kx], lvl[nx], ed[nx], u, v, x, f, lc;
vector<pair<int, int>> d[nx];
vector<int> add[nx], erase[nx], ans;
set<int> s[nx];
void dfs(int u, int p)
{
lvl[u]=lvl[p]+1;
pa[u][0]=p;
for (int i=1; i<kx; i++) pa[u][i]=pa[pa[u][i-1]][i-1];
for (auto [v, id]:d[u]) if (v!=p) ed[v]=id, dfs(v, u);
}
int lca(int u, int v)
{
if (lvl[u]>lvl[v]) swap(u, v);
for (int i=kx-1; i>=0; i--) if (lvl[pa[v][i]]>=lvl[u]) v=pa[v][i];
if (u==v) return u;
for (int i=kx-1; i>=0; i--) if (pa[u][i]!=pa[v][i]) u=pa[u][i], v=pa[v][i];
return pa[u][0];
}
void dfs2(int u, int p)
{
for (auto [v, id]:d[u])
{
if (v!=p)
{
dfs2(v, u);
if (s[v].size()>=k) ans.push_back(id);
for (auto tmp:s[v]) s[u].insert(tmp);
}
}
for (auto tmp:add[u]) s[u].insert(tmp);
for (auto tmp:erase[u]) s[u].erase(tmp);
}
int main()
{
cin.tie(NULL)->sync_with_stdio(false);
cin>>n>>m>>k;
for (int i=1; i<n; i++) cin>>u>>v, d[u].push_back({v, i}), d[v].push_back({u, i});
dfs(1, 1);
for (int i=1; i<=m; i++)
{
cin>>x>>u;
lc=u;
add[u].push_back(i);
for (int j=0; j<x-1; j++) cin>>u, lc=lca(lc, u), add[u].push_back(i);
erase[lc].push_back(i);
}
dfs2(1, 1);
sort(ans.begin(), ans.end());
cout<<ans.size()<<'\n';
for (auto tmp:ans) cout<<tmp<<' ';
}
