#include <bits/stdc++.h>
using namespace std;
#define sz(v) ((int)(v).size())
#define all(v) (v).begin(), (v).end()
#define L(i, j, k) for(int i = (j); i <= (k); ++i)
#define R(i, j, k) for(int i = (j); i >= (k); --i)
std::mt19937 rng(std::chrono::steady_clock::now().time_since_epoch().count());
const int lg=20;
const int MX=1e5+7;
int dp[lg][MX];
void solve() {
int n,m,k;cin>>n>>m>>k;
vector<int> tin(n);
vector<int> val(n,0);
vector<int> resp(n,0);
vector<int> dep(n,0);
vector<int> edpai(n,-1);
vector<int> edgs(n);
vector<vector<int>> adj(n);
L(i,0,n-2){
int a,b;cin>>a>>b;a--;b--;
adj[a].push_back(i);
adj[b].push_back(i);
edgs[i]=a^b;
}
int tmp=0;
edpai[0]=n-1;
auto dfs=[&](auto&& self, int node,int p)->void{
tin[node]=tmp++;
dp[0][node]=p;
dep[node]=dep[p]+1;
L(i,1,lg-1){
dp[i][node]=dp[i-1][dp[i-1][node]];
}
for(auto e:adj[node]){
int a=edgs[e]^node;
if(a==p)continue;
edpai[a]=e;
self(self,a,node);
}
};
dfs(dfs,0,0);
auto lca=[&](int a, int b)->int{
if(dep[a]<dep[b])swap(a,b);
int d=dep[a]-dep[b];
L(i,0,lg-1){
if(d&(1<<i))a=dp[i][a];
}
if(a==b)return a;
R(i,lg-1,0){
if(dp[i][a]!=dp[i][b]){
a=dp[i][a];
b=dp[i][b];
}
}
return dp[0][a];
};
auto solv=[&](vector<int>& vec){
for(auto a:vec)val[a]++;
sort(vec.begin(),vec.end(),[&](int a, int b){
return tin[a]<tin[b];
});
int lcgoat=vec[0];
L(i,1,sz(vec)-1){
int at=lca(vec[i],vec[i-1]);
val[at]--;
lcgoat=lca(at,lcgoat);
}
val[lcgoat]--;
};
L(i,0,m-1){
int k;cin>>k;
vector<int> aux(k);
L(i,0,k-1){
cin>>aux[i];aux[i]--;
}
solv(aux);
}
auto dfsfind=[&](auto&& self, int node, int pai)->int{
resp[edpai[node]]=val[node];
for(auto e:adj[node]){
int a=edgs[e]^node;
if(a==pai)continue;
resp[edpai[node]]+=self(self,a,node);
}
return resp[edpai[node]];
};
dfsfind(dfsfind, 0,0);
vector<int> fina;
L(i,0,n-2){
if(resp[i]>=k)fina.push_back(i+1);
}
cout<<sz(fina)<<"\n";
for(auto a:fina)cout<<a<<" ";
}
int32_t main() {
std::cin.tie(0)->sync_with_stdio(0);
std::cin.exceptions(std::cin.failbit);
int T = 1;
// std::cin >> T;
while(T--) {
solve();
}
return 0;
}
