///roadtoVOI2025
///enjoythejourney
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define fi first
#define se second
#define ii pair<int,int>
#define mp make_pair
#define in(x) freopen(x,"r",stdin)
#define out(x) freopen(x,"w",stdout)
#define bit(x,i) ((x>>i)&1)
#define lc (id<<1)
#define rc ((id<<1)^1)
const int maxn=1e5+7;
vector<ii>adj[maxn];
int p[25][maxn];
int in[maxn],out[maxn];
int h[maxn];
int cnt=0;
int n,m,k;
int t[maxn];
int dinh[maxn];
void dfs(int u,int par)
{
in[u]=++cnt;
for(auto [v,id]:adj[u])if(v!=par){
p[0][v]=u;
dinh[v]=id;
h[v]=h[u]+1;
dfs(v,u);
}
out[u]=cnt;
}
int lca(int u,int v)
{
if(h[u]<h[v])swap(u,v);
int diff=h[u]-h[v];
for(int i=20;i>=0;i--)if(bit(diff,i))u=p[i][u];
if(u==v)return u;
for(int i=20;i>=0;i--)if(p[i][u]!=p[i][v]){
u=p[i][u];
v=p[i][v];
}
return p[0][u];
}
void up(int x,int val)
{
for(;x<maxn;x+=(x&(-x)))t[x]+=val;
}
int get(int x)
{
int res=0;
if(x<=0)return 0;
for(;x;x-=(x&(-x)))res+=t[x];
return res;
}
void sol()
{
cin>>n>>m>>k;
for(int i=1;i<n;i++){
int u,v;
cin>>u>>v;
adj[u].push_back({v,i});
adj[v].push_back({u,i});
}
dfs(1,0);
for(int i=1;i<=20;i++){
for(int j=1;j<=n;j++){
p[i][j]=p[i-1][p[i-1][j]];
}
}
for(int i=1;i<=m;i++){
int s;
cin>>s;
vector<int>v;
for(int j=1;j<=s;j++){
int x;
cin>>x;
v.push_back(x);
}
sort(v.begin(),v.end(),[&](const int &a,const int &b){
return in[a]<in[b];
});
v.push_back(v[0]);
for(int i=0;i<v.size()-1;i++){
int l=lca(v[i],v[i+1]);
up(in[v[i]],1);
up(in[v[i+1]],1);
up(in[l],-2);
}
}
vector<int>ans;
for(int i=1;i<=n;i++){
if(get(out[i])-get(in[i]-1)>=2*k)ans.push_back(dinh[i]);
}
sort(ans.begin(),ans.end());
cout<<ans.size()<<"\n";
for(int x:ans){
cout<<x<<" ";
}
}
signed main(void)
{
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
int t=1;
while(t--){
sol();
}
// you should actually read the stuff at the bottom
return 0;
}
/* stuff you should look for
* int overflow, array bounds
* special cases (n=1?)
* do smth instead of nothing and stay organized
* WRITE STUFF DOWN
* DON'T GET STUCK ON ONE APPROACH
*/
