#include <bits/stdc++.h>
using namespace std;
#define ll long long
vector<pair<ll,ll>> graph[100003];
ll preorder[100003];
ll postorder[100003];
ll iter=0;
ll jmp[100003][19];
ll dep[100003];
ll sum[100003];
void dfs(ll v, ll p){
preorder[v]=iter++;
jmp[v][0]=p;
for (ll i = 1; i<19; i++)jmp[v][i]=jmp[jmp[v][i-1]][i-1];
for (auto [u,ind] : graph[v]){
if (u==p)continue;
dep[u]=dep[v]+1;
dfs(u,v);
}
postorder[v]=iter++;
}
ll lca(ll a, ll b){
if (dep[a]<dep[b])swap(a,b);
for (ll i = 18; i>=0; i--)if (dep[jmp[a][i]]>=dep[b])a=jmp[a][i];
if (a==b)return a;
for (ll i = 18; i>=0; i--)if (jmp[a][i]!=jmp[b][i]){
a=jmp[a][i];
b=jmp[b][i];
}
return jmp[a][0];
}
vector<ll> ans;
void dfs2(ll v, ll p){
for (auto [u,ind] : graph[v]){
if (u==p)continue;
dfs2(u,v);
sum[v]+=sum[u];
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
ll n,m,k;
cin >> n >> m >> k;
for (ll i = 1,v,u; i<n; i++){
cin >> v >> u;
graph[v].push_back({u,i});
graph[u].push_back({v,i});
}
dfs(1,1);
for (ll i = 1,s; i<=m; i++){
cin >> s;
vector<ll> vec(s);
for (ll j = 0; j<s; j++)cin >> vec[j];
sort(vec.begin(),vec.end(),[](ll a, ll b){return preorder[a]<preorder[b];});
vec.push_back(vec[0]);
for (ll j = 0; j<s; j++){
sum[vec[j]]++;
sum[vec[j+1]]++;
sum[lca(vec[j],vec[j+1])]-=2;
}
}
dfs2(1,0);
for (ll v = 1; v<=n; v++){
for (auto [u,ind] : graph[v]){
if (preorder[u]<preorder[v] && postorder[u]>postorder[v] && sum[v]>=2*k){
ans.push_back(ind);
}
}
}
sort(ans.begin(),ans.end());
cout << ans.size() << '\n';
for (auto u : ans)cout << u << ' ';
cout << '\n';
}
