#include <bits/stdc++.h>
#define int long long
using namespace std;
const int NMAX=1e5;
int n, m, k, s[NMAX+1], total[NMAX+1];
vector<pair<int, int>> g[NMAX+1];
unordered_map<int, int> freq[NMAX+1];
void dfs(int nod, int par, int index)
{
//calc muchia par->nod
for(auto &[key, val]:freq[nod])
if(val>0 && val<s[key])
++total[index];
for(auto &[to, edge_id]:g[nod])
{
if(to==par)continue;
dfs(to, nod, edge_id);
if(freq[nod].size() < freq[to].size())
{
swap(freq[nod], freq[to]);
total[index]=total[edge_id];
}
for(auto &[key, val]:freq[to])
{
if(freq[nod][key]==0 && val>0)++total[index];
freq[nod][key]+=val;
if(freq[nod][key]==s[key])--total[index];
}
}
}
signed main()
{
cin>>n>>m>>k;
for(int i=1, x, y; i<n; i++)
{
cin>>x>>y;
g[x].push_back({y, i});
g[y].push_back({x, i});
}
for(int i=1; i<=m; i++)
{
cin>>s[i];
for(int j=1, p; j<=s[i]; j++)
{
cin>>p;
freq[p][i]++;
}
}
dfs(1, 0, 0);
vector<int> care;
for(int i=1; i<n; i++)
if(total[i]>=k)
care.push_back(i);
cout<<care.size()<<'\n';
sort(care.begin(), care.end());
for(auto &x:care)cout<<x<<' ';
return 0;
}
