#include <bits/stdc++.h>
#define DIMN 100010
using namespace std;
int eul[5*DIMN],nv[5*DIMN],first[DIMN];
int d[20][5*DIMN] , el , elem, st[DIMN] , ed[DIMN] , sp[DIMN] , idk[DIMN] , ok[DIMN];
int lg[5*DIMN] , fth[DIMN];
vector <int> v[DIMN];
map <pair <int,int> , int> nr_mch;
void dfs (int nod , int tt ,int niv){
int i,vecin;
fth[nod] = tt;
eul[++elem]=nod;
nv[elem] = niv;
first[nod] = elem; /// prima poz;
for (i=0;i<v[nod].size();i++){
vecin=v[nod][i];
if (vecin != tt){
dfs(vecin , nod ,niv+1);
eul[++elem]=nod;
nv[elem]=niv;
}
}
ed[nod] = elem; /// pana la elem e intervalul
}
int query (int x,int y){
int px,py,len;
px=first[x];
py=first[y];
/// minimul din intervalul px py
/// in d e pozitia din eul unde e nivelul minim
if (px>py)
swap(px,py);
len = py-px+1;
if (nv[ d[lg[len]][px] ] < nv[ d[lg[len]][py-(1<<lg[len])+1] ])
return d[lg[len]][px];
return d[lg[len]][py-(1<<lg[len])+1];
}
int cmp (int x , int y){
return first[x] < first[y];
}
void dfs_sp (int nod,int tt){
int i,vecin;
for (i=0;i<v[nod].size();i++){
vecin=v[nod][i];
if (vecin != tt){
dfs_sp(vecin , nod);
sp[nod]+=sp[vecin];
}
}
}
int main()
{
FILE *fin = stdin;
FILE *fout = stdout;
int n , m , i , x , y , sol , nr , j , frc , powe , nod;
pair <int,int> z;
fscanf (fin,"%d%d%d",&n,&m,&frc);
for (i=1;i<n;i++){
fscanf (fin,"%d%d",&x,&y);
v[x].push_back(y);
v[y].push_back(x);
nr_mch[make_pair(x , y)] = i;
nr_mch[make_pair(y , x)] = i;
}
dfs(1 , 0 , 0);
for (i=2;i<=elem;i++){
lg[i]=lg[i/2]+1;
}
for (i=1;i<=elem;i++){
d[0][i] = i;
}
for (powe=1;powe<=lg[elem];powe++){
for (i=1;i + (1<<powe)-1 <=elem;i++){
if (nv[d[powe-1][i]] < nv[d[powe-1][i + (1<<(powe-1))]])
d[powe][i] = d[powe-1][i];
else d[powe][i] = d[powe-1][i + (1<<(powe-1))];
}
}
/// ai precalculat pe lca in log pt ca ti a fost lene sa faci cu query in o(1)
for (i=1;i<=m;i++){
fscanf (fin,"%d",&nr);
nod = 0;
for (j=1;j<=nr;j++){
fscanf (fin,"%d",&idk[j]);
if (j == 1)
nod = idk[j];
else nod = eul[query (idk[j] , nod)];
}
idk[++nr] = nod; /// sa zicem ca adaugi si lca ul total
sort (idk + 1 , idk + nr + 1 , cmp);
int nra = nr;
for (j=2;j<nra;j++){
idk[++nr] = eul[query(idk[j] , idk[j+1])];
}
sort (idk + 1 , idk + nr + 1 , cmp);
el = 0;
for (j=1;j<=nr;j++){
while (el && ed[st[el]] < first[idk[j]])
el--;
if (el){
sp[idk[j]]++;
sp[st[el]]--;
}
st[++el] = idk[j];
}
}
dfs_sp(1 , 0);
sol = 0;
for (i=1;i<=n;i++){
if (sp[i] >= frc){
ok[++sol] = nr_mch[make_pair(i , fth[i])];
}
}
sort (ok + 1 , ok + sol + 1);
fprintf (fout,"%d\n",sol);
for (i=1;i<=sol;i++)
fprintf (fout,"%d ",ok[i]);
return 0;
}
