#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define ll long long
#define ld long double
#define mp make_pair
const int N=1e5+50,lg=18;
vector<int>E[N];
int n,q,K;
int in[N],tajm,out[N],par[N][lg+1],depth[N];
void DFS1(int u,int p=0){
in[u]=++tajm;
par[u][0]=p;depth[u]=depth[p]+1;
for(int i=1;i<=lg;i++)par[u][i]=par[par[u][i-1]][i-1];
for(auto i:E[u])if(i!=p)DFS1(i,u);
out[u]=tajm;
}
int LCA(int u,int v){
if(depth[u]<depth[v])swap(u,v);
for(int i=lg;i>=0;i--)if(depth[par[u][i]]>=depth[v])u=par[u][i];if(u==v)return u;
for(int i=lg;i>=0;i--)if(par[u][i]!=par[v][i])u=par[u][i],v=par[v][i];return par[u][0];
}
int val[N],dp[N];
vector<int>res;
map<pair<int,int>,int>mapa;
void DFS(int u,int p=0){
dp[u]=val[u];
for(auto i:E[u])if(i!=p)DFS(i,u),dp[u]+=dp[i];
if(p!=0&&dp[u]>=2*K)res.pb(mapa[mp(u,p)]);
}
int main(){
scanf("%i%i%i",&n,&q,&K);
for(int i=1;i<n;i++){
int u,v;scanf("%i%i",&u,&v);
E[u].pb(v),E[v].pb(u);
mapa[{u,v}]=mapa[{v,u}]=i;
}
DFS1(1);
while(q--){
int m;scanf("%i",&m);
int a[m];for(int i=0;i<m;i++)scanf("%i",&a[i]);
sort(a,a+m,[&](int i,int j){return in[i]<in[j];});
for(int i=0;i<m;i++){
int u=a[i],v=a[0];
if(i<m-1)v=a[i+1];
int c=LCA(u,v);
val[u]++,val[v]++;
val[c]-=2;
}
}
DFS(1);
sort(res.begin(),res.end());
printf("%i\n",res.size());
for(auto i:res)printf("%i ",i);printf("\n");
return 0;
}
