#include "bits/stdc++.h"
#include <cstring>
#include <fstream>
using namespace std;
#define forR(i, x) for(int i = 0; i < x; ++i)
#define REP(i, a, b) for(int i = (a); i < (b); ++i)
#define open(s) freopen(((string) s + ".in").c_str(), "r", stdin); freopen(((string) s + ".out").c_str(), "w", stdout)
#define all(i) i.begin(), i.end()
#define boost() cin.sync_with_stdio(0); cin.tie()
typedef long long ll;
typedef pair<int, int> pii;
const int MN = 1e5 + 10, ME=20;
struct edge{int i, ind;};
int anc[MN][ME], dep[MN], n, k;
vector<edge> adj[MN];
vector<int> add[MN], rem[MN], needed;
void fill(int c, int p, int d){
dep[c] = d, anc[c][0] = p;
REP(e, 1, ME) anc[c][e] = anc[c][e-1] == -1 ? -1 : anc[anc[c][e-1]][e-1];
for(auto [i, ind] : adj[c]) if(i != p) fill(i, c, d + 1);
}
int lca(int a, int b){
if(dep[a] > dep[b]) swap(a, b);
for(int e = ME - 1; e >= 0; --e) if(dep[b] - (1 << e) >= dep[a]){
b=anc[b][e];
}
if(a == b) return a;
for(int e = ME - 1; e >= 0; --e) if(anc[a][e] != anc[b][e]){
a = anc[a][e], b=anc[b][e];
}
return anc[a][0];
}
void join(set<int>& a, set<int>& b){
if(a.size() < b.size()) a.swap(b);
a.insert(all(b));
}
set<int> dfs(int c, int p, int pInd){
set<int> has;
for(auto [i, ind] : adj[c]) if(i != p) {
set<int> ret = dfs(i, c, ind);
join(has, ret);
}
for(int i : add[c]) has.insert(i);
for(int i : rem[c]) has.erase(i);
if(has.size() >= k) needed.push_back(pInd);
// cout << c << ' ';
// for(int i : has) cout << i << ' ';
// cout << '\n';
return has;
}
signed main() {
int n, m; cin >> n >> m >> k;
forR(g, n - 1){
int a, b; cin >> a >> b;
adj[a].push_back({b, g+1}); adj[b].push_back({a, g+1});
}
fill(1, -1, 0);
forR(g, m){
int s; cin >> s;
int lc; cin >> lc;
add[lc].push_back(g);
forR(h, s - 1){
int a; cin >> a;
add[a].push_back(g);
lc = lca(lc, a);
}
rem[lc].push_back(g);
}
dfs(1, -1, -1);
cout << needed.size() << '\n';
sort(all(needed));
forR(i, needed.size()) cout << needed[i] << " \n"[i + 1 == needed.size()];
}
