#include<bits/stdc++.h>
using namespace std;
#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define ll long long int
const ll N = 1e5+5 , INF = 1e18 , MOD = 1e9+7;
vector<ll> adj[N] , level(N) , tin(N);
ll timer = 0;
vector<vector<ll>> up(N,vector<ll>(log2(N)+5));
void dfs1(ll s , ll p){
timer++;
tin[s] = timer;
for(auto u : adj[s]){
if(u == p) continue;
level[u] = level[s]+1;
up[u][0] = s;
for(ll i = 1; i <= log2(N); i++) up[u][i] = up[up[u][i-1]][i-1];
dfs1(u,s);
}
}
ll jump(ll a , ll d){
for(ll i = 0; i <= log2(N); i++){
if(d&(1ll<<i)){
a = up[a][i];
}
}
return a;
}
ll lca(ll a , ll b){
if(level[a] > level[b]) swap(a,b);
b = jump(b,level[b]-level[a]);
if(a == b) return a;
for(ll i = log2(N); i >= 0; i--){
if(up[a][i] != up[b][i]){
a = up[a][i];
b = up[b][i];
}
}
return up[a][0];
}
bool comp(ll a , ll b){
return tin[a] < tin[b];
}
vector<ll> cnt(N),sum(N);
void dfs2(ll s , ll p){
sum[s] = cnt[s];
for(auto u : adj[s]){
if(u == p) continue;
dfs2(u,s);
sum[s] += sum[u];
}
}
void solve(){
ll n,m,k;
cin >> n >> m >> k;
vector<tuple<ll,ll,ll>> edge;
for(ll i = 1; i < n; i++){
ll a,b;
cin >> a >> b;
adj[a].push_back(b);
adj[b].push_back(a);
edge.push_back(make_tuple(a,b,i));
}
level[1] = 0;
for(ll i = 0; i <= log2(N); i++) up[1][i] = 0;
dfs1(1,0);
for(ll i = 1; i <= m; i++){
ll s;
cin >> s;
vector<ll> node;
for(ll j = 1; j <= s; j++){
ll x;
cin >> x;
node.push_back(x);
}
sort(node.begin(),node.end(),comp);
node.push_back(node[0]);
for(ll i = 1; i <= s; i++){
ll a = node[i-1];
ll b = node[i];
ll l = lca(a,b);
cnt[a]++;
cnt[b]++;
cnt[lca(a,b)] -= 2;
}
}
dfs2(1,0);
vector<ll> ans;
for(auto u : edge){
ll a,b,ind;
tie(a,b,ind) = u;
if(level[a] > level[b]) swap(a,b);
ll cur = sum[b];
cur /= 2;
if(cur >= k){
ans.push_back(ind);
}
}
cout << ans.size() << "\n";
for(auto u : ans) cout << u << " ";
}
int main(){
fast;
ll tc = 1;
// cin >> tc;
while(tc--) solve();
return 0;
}
