#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define sz(x) (int)x.size()
#define ALL(v) v.begin(),v.end()
#define MASK(k) (1LL << (k))
#define BIT(x, i) (((x) >> (i)) & 1)
#define oo (ll)1e18 + 10
#define INF (ll)1e9
#define MOD (ll)(998244353)
using namespace std;
template<class T1, class T2>
bool maximize(T1 &a, T2 b){if(a < b){a = b; return true;} return false;}
template<class T1, class T2>
bool minimize(T1 &a, T2 b){if(a > b){a = b; return true;} return false;}
template<class T1, class T2>
void add(T1 &a, T2 b){a += b; if(a >= MOD) a -= MOD;}
template<class T1, class T2>
void sub(T1 &a, T2 b){a -= b; if(a < 0) a += MOD;}
template<class T>
void cps(T &v){sort(ALL(v)); v.resize(unique(ALL(v)) - v.begin());}
const int maxN = 1e5 + 10, LOG = 17;
int N, M, K;
vector<pair<int, int>> adj[maxN];
int idEdge[maxN], in[maxN], out[maxN], timer, h[maxN], d[maxN][LOG], cnt[maxN];
void dfs(int u, int p = -1){
in[u] = ++timer;
for(auto o: adj[u]){
int v = o.fi, id = o.se;
if(v == p) continue;
h[v] = h[u] + 1;
d[v][0] = u;
for(int i = 1; i < LOG; i++){
d[v][i] = d[d[v][i - 1]][i - 1];
}
idEdge[v] = id;
dfs(v, u);
}
out[u] = timer;
}
int lca(int u, int v){
if(h[u] < h[v]) swap(u, v);
int delta = h[u] - h[v];
for(int i = 0; i < LOG; i++) if(BIT(delta, i)){
u = d[u][i];
}
if(u == v) return u;
for(int i = LOG - 1; i >= 0; i--) if(d[u][i] != d[v][i]){
u = d[u][i];
v = d[v][i];
}
return d[u][0];
}
void solve(){
cin >> N >> M >> K;
for(int i = 1; i < N; i++){
int u, v; cin >> u >> v;
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
dfs(1);
for(int p = 1; p <= M; p++){
int k; cin >> k;
vector<int> index;
for(int i = 1; i <= k; i++){
int x; cin >> x;
index.push_back(x);
}
sort(ALL(index), [&](int u, int v){return in[u] < in[v];});
// if(p == 2)
for(int i = 0; i < sz(index); i++){
// if(i + 1 < sz(index)) cout << in[index[i]] << ' ' << in[index[i + 1]] << ' ' << in[lca(index[i], index[i + 1])] << '\n';
// cnt[in[index[i]]]++;
if(i + 1 < sz(index)){
cnt[in[index[i]]]++;
cnt[in[index[i + 1]]]++;
cnt[in[lca(index[i], index[i + 1])]] -= 2;
}
}
// cout << '\n';
}
for(int i = 1; i <= N; i++) cnt[i] += cnt[i - 1];
// cout << '\n';
vector<int> ans;
for(int i = 2; i <= N; i++){
if(cnt[out[i]] - cnt[in[i] - 1] >= K) ans.push_back(idEdge[i]);
// cout << i << ' ' << cnt[out[i]] - cnt[in[i] - 1] << '\n';
}
cout << sz(ans) << '\n';
for(int x: ans) cout << x << ' ';
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
// freopen("bdbang.inp","r",stdin);
// freopen("bdbang.out","w",stdout);
int T = 1;
// cin >> T;
for(; T > 0; T--) solve();
return 0;
}
