#include <bits/stdc++.h>
using namespace std;
#define int long long
#pragma GCC optimize("O3,unroll-loops")
#define ii pair<int,int>
#define fir first
#define sec second
#define pb push_back
const int maxn=1e5;
vector<ii>adj[maxn+2];
int n,m,k,sz[maxn+2];
vector<int>isi[maxn+2],ans;
map<int,int>freq[maxn+2];
int slh[maxn+2];
void dfs(int cur,int par,int edge){
for(auto [x,id] : adj[cur]){
if(x==par)continue;
dfs(x,cur,id);
if(freq[x].size()>freq[cur].size()){
swap(freq[x],freq[cur]);
swap(slh[x],slh[cur]);
}
for(auto y : freq[x]){
freq[cur][y.fir]+=y.sec;
if(freq[cur][y.fir]==sz[y.fir]){
slh[cur]++;
}
}
}
for(auto x : isi[cur]){
freq[cur][x]++;
if(freq[cur][x]==sz[x]){
slh[cur]++;
}
}
if(freq[cur].size()-slh[cur]>=k){
ans.pb(edge);
}
}
signed main(){
cin>>n>>m>>k;
for(int q=1;q<n;q++){
int u,v;
cin>>u>>v;
adj[u].pb({v,q});
adj[v].pb({u,q});
}
for(int q=1;q<=m;q++){
cin>>sz[q];
for(int w=1;w<=sz[q];w++){
int x; cin>>x;
isi[x].pb(q);
}
}
dfs(1,0,0);
sort(ans.begin(),ans.end());
cout<<ans.size()<<endl;
for(auto x : ans){
cout<<x<<' ';
}
cout<<endl;
}
