#include<bits/stdc++.h>
using namespace std;
const int mx=1e5+5;
typedef long long ll;
int mod=1e9+7;
const int MXm=22;
#define F first
#define S second
const int inf=1e9+10;
vector<int>adj[mx]; vector<pair<int,int>>edges;vector<int>ans;
int depth[mx],dp[20][mx],sz[mx], active[mx];
vector<int>a[mx]; set<int>S[mx]; vector<int>E[mx];
void dfs(int node,int par){
dp[0][node]=par;
sz[node]=1;
for(int j=1;j<19;j++){
dp[j][node]=dp[j-1][dp[j-1][node]];
}
for(auto it:adj[node]){
if(it==par){continue;}
depth[it]=depth[node]+1;
dfs(it,node);
sz[node]+=sz[it];
}
return;
}
int kth(int node,int x){
for(int i=0;i<19;i++){
if(x&(1<<i)){
x-=(1<<i);
node=dp[i][node];
}
}
return node;
}
int lca(int a,int b){
if(depth[b]<depth[a]){swap(a,b);}
int dis=depth[b]-depth[a];
b=kth(b,dis);
// cout<<b;
if(a==b){return a;}
for(int j=19;j>=0;j--){
int aa=dp[j][a];int bb=dp[j][b];
if(aa==bb){continue;}
a=aa;b=bb;}
return dp[0][a];
}
int n,m,k;
map<pair<int,int>,int>mp;
vector<int>vec[mx];
void dfs2(int node,int par,bool keep){
int mx2=-1;int bigchild=-1;
for(auto it:adj[node]){
if(it==par){continue;}
if(sz[it]>mx2){mx2=sz[it];bigchild=it;}
}
for(auto it:adj[node]){
if(it!=bigchild&&it!=par){
dfs2(it,node,0);
}
}
if(bigchild!=-1){
dfs2(bigchild,node,1);
swap(S[bigchild],S[node]);
}
for(auto it:adj[node]){
if(it!=bigchild&&it!=par){
for(auto &j:S[it]){
S[node].insert(j);
}
}
/*
if(it!=par){
if(vec[it].size()){mp[{min(it,node),max(it,node)}]++;}
}
*/
}
for(auto it:E[node]){
if(S[node].find(it)!=S[node].end()){
S[node].erase(it);
}
}
if(S[node].size()>=k){
ans.push_back(mp[{node,par}]);
}
}
void test(){
for(int i=1;i<=n;i++){
for(int j=i+1;j<=n;j++){
if(mp[{i,j}]){
cout<<i<<" "<<j<<endl;
}
}
}
}
void test2(){
cout<<ans.size()<<endl;
sort(ans.begin(),ans.end());
for(auto it:ans){
cout<<it<<" ";
}
}
int main(){
ios_base::sync_with_stdio(0) ;
cin.tie(0) ;
cin>>n>>m>>k;
for(int i=0;i<n-1;i++){
int a,b;cin>>a>>b;
mp[{a,b}]=mp[{b,a}]=i+1;
edges.push_back({a,b});
adj[a].push_back(b);
adj[b].push_back(a);
}
dfs(1,0);
for(int i=0;i<m;i++){
int s;cin>>s;
int now=0;
for(int j=0;j<s;j++){
int x;cin>>x;
if(now==0){
now=x;
}else{
now=lca(now,x);
}
active[i]=1;
S[x].insert(i);
}
E[now].push_back(i);
}
dfs2(1,0,0);
test2();
}
