#include <bits/stdc++.h>
using namespace std;
int n,m,k;
vector<pair<int,int>> con[100005];
pair<int,int> parent[100005];
int anc[100005][17];
int tin[100005],tout[100005],timer;
void dfs(int nod)
{
tin[nod] = ++timer;
for(auto [adj,id]:con[nod])
{
if(adj==anc[nod][0])
continue;
anc[adj][0] = nod;
parent[adj] = {nod,id};
dfs(adj);
}
tout[nod] = ++timer;
}
bool isanc(int x, int y)
{
return (tin[x]<=tin[y] && tout[x]>=tout[y]);
}
int lca(int x, int y)
{
if(isanc(x,y))
return x;
if(isanc(y,x))
return y;
for(int p=16;p>=0;p--)
if(!isanc(anc[x][p],y))
x = anc[x][p];
return anc[x][0];
}
bool cmp(int x, int y)
{
return tin[x] < tin[y];
}
int cnt[100005], auxcnt[100005];
void baga(int x, int y)
{
assert(isanc(x,y));
/*while(y!=x)
{
//cerr<<y<<" zzz\n";
cnt[parent[y].second]++;
y = parent[y].first;
}*/
auxcnt[y]++;
auxcnt[x]--;
}
void dfs2(int nod)
{
for(auto [adj,id]:con[nod])
{
if(adj==parent[nod].first)
continue;
dfs2(adj);
cnt[id] = auxcnt[adj];
auxcnt[nod] += auxcnt[adj];
}
}
int main()
{
ios_base::sync_with_stdio(0);cin.tie(0);
cin>>n>>m>>k;
int u,v;
for(int i=1;i<n;i++)
{
cin>>u>>v;
con[u].push_back({v,i});
con[v].push_back({u,i});
}
anc[1][0]=1;
dfs(1);
for(int p=1;p<17;p++)
for(int i=1;i<=n;i++)
anc[i][p] = anc[anc[i][p-1]][p-1];
while(m--)
{
int nr;
cin>>nr;
vector<int> v(nr);
for(int i=0;i<nr;i++)
cin>>v[i];
sort(v.begin(),v.end(),cmp);
map<int,int> ap;
vector<int> newv;
for(int i=0;i<nr;i++)
{
if(!ap[v[i]])
{
newv.push_back(v[i]);
ap[v[i]]=1;
}
}
for(int i=0;i+1<nr;i++)
{
int x = lca(v[i],v[i+1]);
//cerr<<v[i]<<" "<<v[i+1]<<" lca "<<x<<"\n";
if(!ap[x])
{
newv.push_back(x);
ap[x]=1;
}
}
sort(newv.begin(),newv.end(),cmp);
vector<int> aux;
aux.push_back(newv[0]);
for(int i=1;i<newv.size();i++)
{
int x = newv[i];
while(!aux.empty() && !isanc(aux.back(),x))
{
aux.pop_back();
}
baga(aux.back(),x);
aux.push_back(x);
}
}
dfs2(1);
vector<int> sol;
for(int i=1;i<n;i++)
if(cnt[i]>=k)
sol.push_back(i);
cout<<(int)sol.size()<<"\n";
for(int x:sol)
cout<<x<<" ";
return 0;
}
