#include "bits/stdc++.h"
using namespace std;
#define task ""
#define ll long long
#define endl '\n'
#define fi first
#define se second
#define vall(a) (a).begin(), (a).end()
#define sze(a) (int)a.size()
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ep emplace_back
#define pb push_back
#define pf push_front
const ll mod = 1e9 + 7;
const int N = 2e5 + 5;
const ll oo = 1e18;
bool START;
int n, m, k, t = 0, dp[N], in[N], lg[N], h[N];
vector<pii> adj[N];
pii st[N][19];
void dfsb(int u, int p) {
in[u] = ++t;
st[t][0] = make_pair(h[u], u);
for (auto [v, id] : adj[u]) {
if (v == p) continue;
h[v] = h[u] + 1;
dfsb(v, u);
st[++t][0] = make_pair(h[u], u);
}
}
void build() {
dfsb(1, 0);
for (int i = 2; i <= t; ++i) lg[i] = lg[i >> 1] + 1;
for (int i = 1; (1 << i) <= t; ++i) {
for (int j = 1; j + (1 << i) - 1 <= t; ++j) {
st[j][i] = min(st[j][i - 1], st[j + (1 << (i - 1))][i - 1]);
}
}
}
int lca(int u, int v) {
if (in[u] < in[v]) swap(u, v);
int k = lg[in[u] - in[v] + 1];
return min(st[in[u] - (1 << k) + 1][k], st[in[v]][k]).se;
}
bool cmp(int a, int b) {
return in[a] < in[b];
}
vector<int> ans;
void dfs(int u, int p) {
for (auto[v, id] : adj[u]) {
if (v == p) continue;
dfs(v, u);
if (dp[v] >= k) ans.pb(id);
dp[u] += dp[v];
}
}
int a[N];
inline void solve() {
build();
while(m--) {
int k; cin >> k;
for (int i = 1; i <= k; ++i) cin >> a[i];
sort(a + 1, a + 1 + k, cmp);
int lck = lca(a[k], a[1]);
++dp[a[1]];
++dp[a[k]];
dp[lck] -= 2;
for (int i = 2; i <= k; ++i) {
lck = lca(a[i], a[i - 1]);
++dp[a[i]];
++dp[a[i - 1]];
dp[lck] -= 2;
}
}
dfs(1, 0);
cout << sze(ans) << endl;
for (int i : ans) cout << i << " ";
}
inline void input() {
cin >> n >> m >> k;
k <<= 1ll;
for (int i = 1; i < n; ++i) {
int u, v;
cin >> u >> v;
adj[u].pb(make_pair(v, i));
adj[v].pb(make_pair(u, i));
}
return solve();
}
bool END;
int main() {
if(fopen(task ".inp", "r")) {
freopen(task ".inp", "r", stdin);
freopen(task ".out", "w", stdout);
}
ios_base::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
input();
cerr << endl << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << 's' << endl;
cerr << "Memory: " << fabs ((&END - &START)) / 1048576.0 << "MB\n";
return 0;
}
