#include <bits/stdc++.h>
#define ff first
#define ss second
#define endl "\n"
#define all(x) (x).begin(), (x).end()
using namespace std;
const int INF = (int) 1e9;
const int mod = (int) 1e9+7;
const int MAXN = (int) 3e5+5;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
int n,m,k;
vector<int> adj[MAXN];
int fake[MAXN];
int cnt = 1;
int arr[MAXN];
vector<int> nums[MAXN];
map<pii,int> mp;
map<pii,int> edge;
vector<pii> query;
vector<set<int>> sets(MAXN);
vector<int> ans;
int pare[MAXN];
void dfs(int v,int par){
fake[v] = cnt++;
for(auto u:adj[v]){
if(u == par)continue;
dfs(u,v);
arr[fake[u]] = cnt-1;
query.push_back({fake[u],cnt-1});
}
}
struct BIT{
vector<int> bit;
int n;
BIT(int l){
this->n = l+1;
bit.assign(l+1,0);
}
void upd(int pos,int val){
for(;pos<n;pos+=pos&-pos){
bit[pos]+=val;
}
}
int get(int pos){
int ret = 0;
for(;pos>0;pos-=pos&-pos){
ret+=bit[pos];
}
return ret;
}
};
void dfs2(int v,int par){
if(adj[v].size() == 1 && par!=-1){
for(auto u:nums[v])sets[v].insert(u);
if((sets[v].size()-mp[{fake[v],arr[fake[v]]}])>=k){
ans.push_back(edge[{min(v,par),max(v,par)}]);
}
pare[v] = v;
return;
}
int num = 0;
for(auto u:adj[v]){
if(u!=par){
dfs2(u,v);
if(num == 0 || sets[pare[u]].size() > sets[num].size()){
num = pare[u];
}
}
}
for(auto u:adj[v]){
if(u!=par && pare[u]!=num){
for(auto c:sets[pare[u]]){
sets[num].insert(c);
}
}
}
for(auto u:nums[v]){
sets[num].insert(u);
}
if((sets[num].size()-mp[{fake[v],arr[fake[v]]}])>=k){
ans.push_back(edge[{min(v,par),max(v,par)}]);
}
pare[v] = num;
}
void solve(){
cin >> n >> m >> k;
for(int i=0;i<n-1;i++){
int a,b;
cin >> a >> b;
edge[{min(a,b),max(a,b)}] = i+1;
adj[a].push_back(b);
adj[b].push_back(a);
}
dfs(1,-1);
arr[1] = n;
query.push_back({1,n});
multiset<pii> ranges;
BIT bt(n);
for(int i=0;i<m;i++){
int s;
cin >> s;
int mini =INF;
int maxi = 0;
for(int j=0;j<s;j++){
int a;
cin >> a;
nums[a].push_back(i+1);
mini = min(mini,fake[a]);
maxi = max(maxi,fake[a]);
}
ranges.insert({mini,maxi});
bt.upd(maxi,1);
}
sort(all(query));
for(auto u:query){
while(!ranges.empty() && ranges.begin()->ff < u.ff){
bt.upd(ranges.begin()->ss,-1);
ranges.erase(ranges.begin());
}
mp[u] = bt.get(u.ss);
}
dfs2(1,-1);
cout << ans.size() << endl;
sort(all(ans));
for(auto u:ans){
cout << u << " ";
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);cout.tie(nullptr);
#ifdef Local
freopen("in.txt","r",stdin);
freopen("out.txt","w",stdout);
#endif
int t=1;
//cin>>t;
while(t--){
solve();
}
#ifdef Local
cout<<endl<<fixed<<setprecision(2)<<1000.0 * clock() / CLOCKS_PER_SEC<< " milliseconds ";
#endif
}
