#include <bits/stdc++.h>
#define int long long
#define pi pair<int,int>
#define pb push_back
#define V vector
#define vi V<int>
#define mi map<int,int>
#define MOD 1000000007
#define MOD2 998244353
#define mp make_pair
#define ins insert
#define qi queue<int>
#define pqi priority_queue<int>
#define si set<int>
#define v2i V<vi>
#define v3i V<v2i>
#define v4i V<v3i>
#define v5i V<v4i>
#define INF 1e18
#define all(x) begin(x), end(x)
#define sz(x) (int) (x).size()
#define fastio ios_base::sync_with_stdio(false); cin.tie(nullptr);
#define endl "\n"
#define lb lower_bound
#define ub upper_bound
#define print(x) cout << x<<" ";
#define vpi V<pi>
#define Y cout<<"YES"<<endl;
#define NO cout<<"NO"<<endl;
#define msi multiset<int>
#define F first
#define S second
#define ld long double
#define RE return;
#define IMP cout<<-1<<endl;return;
using namespace std;
template <typename T>
std::istream& operator>>(std::istream& in, std::vector<T>& vec) {
for (T& x : vec) {
in >> x;
}
return in;
}
vi cnt;
V<mi> arr;
v2i adj;
int k;
map<pi, int> edge;
si ans;
mi dfs(int node, int p){
mi curr = arr[node];
for(auto &x: adj[node])if(x!=p){
mi nxt = dfs(x, node);
if(sz(nxt)<sz(curr)) curr.swap(nxt);
for(auto &z: nxt){
curr[z.F] += z.S;
if(curr[z.F] == cnt[z.F]) curr.erase(z.F);
}
}
if(sz(curr)>=k) ans.ins(edge[{node,p}]);
return curr;
}
signed main(){
int n,m;cin>>n>>m>>k; cnt.resize(m); adj.resize(n); arr.resize(n);
for(int i=1; i<n; i++){
int x,y; cin>>x>>y; x--;y--;
edge[{x,y}]=i; edge[{y,x}]=i;
adj[x].pb(y); adj[y].pb(x);
}
for(int i=0; i<m; i++){
int s; cin>>s;
cnt[i]=s;
while(s--){
int t; cin>> t;
arr[t-1][i]++;
}
}
dfs(0,0);
cout<<sz(ans)<<endl;
for(auto &x: ans) cout<<x<<" ";
}
