#include <bits/stdc++.h>
#define speed ios_base::sync_with_stdio(0); cin.tie(0)
#define all(x) (x).begin(),(x).end()
#define F first
#define S second
using namespace std;
typedef long long ll;
typedef double db;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const ll MAX=1e5+10,P=998244353;
const ll INF=0x3f3f3f3f,oo=0x3f3f3f3f3f3f3f3f;
int n,m,k;
vector<pii> G[MAX];
vector<int> sel[MAX];
int BIT[MAX*2];
void update(int x,int val) {
while (x<MAX) {
BIT[x]+=val;
x+=(-x&x);
}
}
int query(int x) {
ll ans=0;
while (x) {
ans+=BIT[x];
x-=(-x&x);
}
return ans;
}
int tme=1;
int in[MAX],out[MAX];
int up[MAX][20];
int dep[MAX];
void dfs(int v,int p) {
dep[v]=dep[p]+1;
up[v][0]=p;
for (int i=1;i<20;i++) up[v][i]=up[up[v][i-1]][i-1];
in[v]=tme++;
for (auto [i,w]:G[v]) {
if (i==p) continue;
dfs(i,v);
}
out[v]=tme++;
}
int lca(int a,int b) {
if (dep[a]<dep[b]) swap(a,b);
int mv=dep[a]-dep[b];
for (int i=0;i<20;i++) {
if (mv&(1<<i)) a=up[a][i];
}
if (a==b) return a;
for (int i=19;i>=0;i--) {
if (up[a][i]!=up[b][i]) {
a=up[a][i];
b=up[b][i];
}
}
return up[a][0];
}
void pth(int a,int b) {
int ans=lca(a,b);
// cout<<a<<" "<<b<<" "<<ans<<" abans\n"<<flush;
update(in[a],1);
update(in[b],1);
update(in[ans],-2);
}
void dfs2(int v,int p,int id,vector<int>& ans) {
if (v!=1 and query(out[v])-query(in[v]-1)>=2*k) ans.push_back(id);
for (auto [i,w]:G[v]) {
if (i==p) continue;
dfs2(i,v,w,ans);
}
}
int main() {
speed;
cin>>n>>m>>k;
for (int i=1;i<n;i++) {
int a,b;
cin>>a>>b;
G[a].emplace_back(b,i);
G[b].emplace_back(a,i);
}
dep[1]=0;
dfs(1,1);
// for (int i=1;i<=n;i++) {
// cout<<in[i]<<" "<<out[i]<<" inout\n";
// }
for (int i=1;i<=m;i++) {
// cout<<i<<"\n"<<flush;
int s;
cin>>s;
for (int j=0;j<s;j++) {
int x;
cin>>x;
sel[i].push_back(x);
}
if (s<=1) continue;
sort(all(sel[i]),[=](int a,int b) {
return in[a]<in[b];
});
for (int j=0;j<s;j++) {
pth(sel[i][j],sel[i][(j+1)%s]);
}
// for (int i=1;i<=n;i++) {
// cout<<query(out[i])-query(in[i]-1)<<" ";
// }
// cout<<"\n";
}
// cout<<"sgfhfh\n"<<flush;
vector<int> ans;
dfs2(1,1,0,ans);
// for (int i=1;i<=n;i++) {
// cout<<query(out[i])-query(in[i]-1)<<" ";
// }
// cout<<"\n";
cout<<ans.size()<<"\n";
sort(all(ans));
for (int i:ans) cout<<i<<" ";
cout<<"\n";
return 0;
}
/*
6 3 2
1 3
2 3
3 4
6 4
4 5
4 1 3 2 5
2 6 3
2 3 2
*/
