#include <bits/stdc++.h>
#define DIMN 100010
using namespace std;
int ok[DIMN],lvl[DIMN] , f[DIMN] , d[DIMN] , l[DIMN] , up[DIMN] , fth[20][DIMN];
int lg[DIMN] , poz[DIMN];
int lnt = 0;
map <pair <int,int> , int> mc , nr_mch;
pair <int,int> muchie[DIMN];
stack <int > st;
vector <int> v[DIMN] , w[DIMN] , dfs_tree[DIMN] , tr[DIMN] ;
vector <pair <int,int> > aint[DIMN];
int x;
void precalc (int nod){
int i,vecin;
d[nod]=1;
f[nod]=1;
for (i=0;i<v[nod].size();i++){
vecin=v[nod][i];
if (!f[vecin]){
lvl[vecin]=1+lvl[nod];
dfs_tree[nod].push_back(vecin);
precalc (vecin);
d[nod]+=d[vecin];
}
}
}
void dfs_lant(int nod,int tata){
int i,vecin,ok=0,maxi,fiu;
fth[0][nod] = tata;
f[nod] = 1;
maxi=0;
fiu=0;
for (i=0;i<dfs_tree[nod].size();i++){
vecin=dfs_tree[nod][i];
if (vecin != tata){
ok=1;
dfs_lant(vecin,nod);
if (d[vecin]>maxi){
maxi=d[vecin];
fiu=vecin;
}
}
}
if (!ok){ /// frunza
lnt++;
l[nod]=lnt; /// lantul din care apartine
w[lnt].push_back(nod);
}else { /// unim cu poz
w[l[fiu]].push_back(nod);
l[nod]=l[fiu];
for (i=0;i<dfs_tree[nod].size();i++){
vecin=dfs_tree[nod][i];
if (vecin!=tata && vecin!=fiu)
up[l[vecin]]=nod; /// din lantul vecinului trecem in lantul nodului
}
}
}
pair <int,int> lca (int n , int x , int y){
int dif , p2 , swapped = 0;
//if (x == 1 && y == 5)
// printf ("a");
/// aducem pe ac nivel
if (lvl[x] < lvl[y]){
swapped = 1;
swap(x , y); /// x e mai jos
}
dif = lvl[x] - lvl[y] - 1;
/// stramosul dif al lui x
while (dif > 0 && x!=0){
x=fth[lg[dif]][x];
dif=dif-(1<<lg[dif]);
}
/// acum sunt pe acelasi nivel
if (fth[0][x] == y){ /// y era tatal lui x
if (!swapped)
return make_pair(x , -1);
else return make_pair(-1 , x);
}
if (dif != -1)
x = fth[0][x];
for (p2 = lg[n] ; p2>=0 ; p2--){
if (fth[p2][x] != fth[p2][y]){
x = fth[p2][x];
y = fth[p2][y];
}
}
if (!swapped)
return make_pair(x , y);
else return make_pair(y , x);
}
inline void lazy_update (int lant , int nod,int st,int dr){
if (!tr[lant][nod]) /// nu ii trb lazy
return;
if (st<dr){ /// nu e frunza
tr[lant][2*nod]+=tr[lant][nod]; /// pass lazy
tr[lant][2*nod+1]+=tr[lant][nod];
}
aint[lant][nod].first+=tr[lant][nod];
tr[lant][nod]=0;
}
void update_aint (int lant , int nod , int st , int dr , int l , int r , int val , int lts){
int mid = (st + dr)/2;
lazy_update (lant , nod,st,dr);
if (aint[lant][nod].second == lts) /// latest influenteaza aici
return;
if (l <= st && dr <= r){
tr[lant][nod] += val; /// la tot intervalul se adauga val
aint[lant][nod].second = lts;
lazy_update (lant , nod,st,dr);
return;
}
if (l <= mid)
update_aint (lant , 2*nod , st , mid , l , r, val , lts);
if (mid+1 <= r)
update_aint (lant , 2*nod+1 , mid+1 , dr , l , r, val , lts);
lazy_update (lant , 2*nod,st,mid);
lazy_update (lant , 2*nod+1,mid+1,dr);
}
void update (int x , int y , int val , int lts){
if (l[x]!=l[y]){ /// avansam
if (lvl[up[l[x]]]>lvl[up[l[y]]]){
update(up[l[x]] , y , val , lts);
update_aint( l[x] , 1 , 0 , w[l[x]].size()-1 , 0 , poz[x] , val , lts);
}
else {
update (x,up[l[y]] , val , lts);
update_aint(l[y],1,0,w[l[y]].size()-1,0,poz[y] , val , lts);
}
}
else {
return update_aint(l[x],1,0,w[l[x]].size()-1,min(poz[y] , poz[x]),max(poz[y] , poz[x]) , val , lts);
}
}
int query_aint (int lant,int nod,int st,int dr,int px){
int mid;
lazy_update(lant , nod , st , dr);
if (st == dr)
return aint[lant][nod].first;
mid=(st+dr)/2;
if (px<=mid)
return query_aint(lant,2*nod,st,mid,px);
else
return query_aint(lant,2*nod+1,mid+1,dr,px);
}
int main()
{
FILE *fin = stdin;
FILE *fout = stdout;
int n, m , i , x , y , p , vecin, sol , nr , j , a , b , frc;
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;
muchie[i] = make_pair(x , y);
}
for (i=1;i<=n;i++){
if (!f[i])
precalc(i);
}
memset (f , 0 , sizeof ( f ));
for (i=1;i<=n;i++){
if (!f[i])
dfs_lant(i , 0);
}
/// fiecare nod al catelea e
for (i=1;i<=lnt;i++){
reverse(w[i].begin(),w[i].end());
p=0;
for (vector <int> :: iterator j=w[i].begin();j!=w[i].end();j++){
/// pozitia lui din lantul curent
vecin=*j;
poz[vecin]=p;
p++;
}
}
/// folosesti aint
for (i=1;i<=lnt;i++){
aint[i].resize(w[i].size()*5);
tr[i].resize(w[i].size()*5);
}
/// ai precalculat pentru heavy
for (i=2;i<=n;i++){
lg[i]=lg[i/2]+1;
}
int k = 1;
while ((1<<k)<=n){
for (i=1;i<=n;i++){
fth[k][i] = fth[k-1][fth[k-1][i]] ;
}
k++;
}
/// 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);
for (j=1;j<=nr;j++){
fscanf (fin,"%d",&b);
if (j == 1){
a = b;
}
else {
z = lca (n , a , b);
if (z.first != -1)
update (a , z.first , 1 , i ); /// si cu latest
if (z.second != -1)
update (b , z.second , 1 , i); /// si cu latest
if (z.first != -1)
a = fth[0][z.first];
}
}
}
sol = 0;
for (i=1;i<=n;i++){
if (query_aint(l[i] , 1 , 0 , w[l[i]].size() - 1 , poz[i]) >= frc){
ok[++sol] = nr_mch[make_pair(i , fth[0][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;
}
