#include <bits/stdc++.h>
//#pragma GCC optimize ("O3")
//#pragma GCC optimize ("Ofast")
#define F first
#define S second
#define MT make_tuple
#define MP make_pair
#define SZ(a) ((int)(a).size())
#define PB push_back
#define LEFT(i) (2*(i))
#define RIGHT(i) (2*(i)+1)
#define PAR(i) ((i)/2)
#define ALL(a) (a).begin(), (a).end()
#define END(s) {cout << s;return;}
using namespace std;
typedef long long ll;
typedef pair<ll, ll> ii;
std::vector<std::vector<ii> > e,p;
std::vector<std::vector<int> > d;
std::vector<ii> so;
ll n, m, k;
int lgn=0, cnt=0;
void rek(int a, int f){
p[a][0].F=f;
so[a].F=cnt++;
for(auto x: e[a])
if(x.F!=f)
rek(x.F, a);
so[a].S=cnt++;
}
bool ancof(int a, int x){
if(a==-1 || x==-1)
return false;
return so[a].F<=so[x].F && so[x].S<=so[a].S;
}
int upd(int lca, int b){
// fprintf(stderr, "%d %d\n", lca, b);
for(int k=lgn-1; !ancof(lca,b); ) {
while(k>0 && (p[lca][k].F==-1 || ancof(p[lca][k].F, b)))
k--;
p[lca][k].S++;
lca=p[lca][k].F;
}
return lca;
}
int lca(int lca, int b){
for(int k=lgn-1; !ancof(lca,b); ) {
while(k>0 && (p[lca][k].F==-1 || ancof(p[lca][k].F, b)))
k--;
lca=p[lca][k].F;
}
return lca;
}
int main(){
scanf("%lld %lld %lld", &n, &m, &k);
while ((1<<lgn)<n)
lgn++;
p.resize(n);
for(int i=0; i<n; i++)
p[i].resize(lgn,{-1,0});
e.resize(n);
d.resize(m);
so.resize(n);
// fprintf(stderr,"%ld\n", clock());
for(int i=0; i<n-1; i++){
int a, b; scanf("%d %d", &a, &b);
a--; b--;
e[a].PB({b,i+1});
e[b].PB({a,i+1});
}
for(int i=0; i<m; i++){
int s; scanf("%d", &s);
d[i].resize(s);
for(int j=0; j<s; j++){
scanf("%d", &d[i][j]);
d[i][j]--;
}
}
// fprintf(stderr,"%ld\n", clock());
rek(0,-1);
// fprintf(stderr,"%ld\n", clock());
for(int j=1; j<lgn; j++)
for(int i=0; i<n; i++)
if(p[i][j-1].F!=-1)
p[i][j].F=p[p[i][j-1].F][j-1].F;
// fprintf(stderr,"%ld\n", clock());
for(int i=0; i<m; i++){
sort(ALL(d[i]),[&](int a, int b){
return so[a].F<so[b].F;
});
int s=SZ(d[i]);
std::vector<int> st;
st.PB(d[i][0]);
for(int j=1; j<s; j++){
if(ancof(st.back(),d[i][j])){
upd(d[i][j],st.back());
if(SZ(st)>1 && ancof(st[SZ(st)-2],st.back()))
st.pop_back();
} else{
int a=st.back();
st.pop_back();
if(!st.empty() && !ancof(st.back(),d[i][j])){
a=st.back();
st.pop_back();
st.PB(upd(a,d[i][j]));
}
upd(d[i][j],a);
}
st.PB(d[i][j]);
}
}
for(int j=lgn-1; j>0; j--)
for(int i=0; i<n; i++)
if(p[i][j].F!=-1){
p[i][j-1].S+=p[i][j].S;
p[p[i][j-1].F][j-1].S+=p[i][j].S;
}
std::vector<int> out;
for(int i=1; i<n; i++){
if(p[i][0].S>=k)
for(auto x: e[i])
if(x.F==p[i][0].F){
out.PB(x.S);
break;
}
}
sort(ALL(out));
printf("%d\n", SZ(out));
for(int i: out)
printf("%d ", i);
printf("\n");
}
