#include <bits//stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> using namespace std; using namespace __gnu_pbds; typedef tree<long long, null_type, less<long long>, rb_tree_tag, tree_order_statistics_node_update> ordered_set; typedef tree<long long, null_type, less_equal<long long>, rb_tree_tag, tree_order_statistics_node_update> ordered_multiset; #define ll long long #define iloop(m, h) for (auto i = m; i != h; i += (m < h ? 1 : -1)) #define jloop(m, h) for (auto j = m; j != h; j += (m < h ? 1 : -1)) #define kloop(m, h) for (auto k = m; k != h; k += (m < h ? 1 : -1)) #define pll pair<ll, ll> #define INF 1000000000000000 #define MOD1 1000000007 #define MOD2 998244353 #define MOD3 1000000009 ll n, m, t, g; vector<ll> adj[100005]; ll pre[100005], unpre[100005], cnt = 0; ll ccnt[100005], ced[100005]; ll twok[100005][20], dpt[100005]; pll a[100005]; void dfs1(ll nd, ll pr, ll dp) { dpt[nd] = dp; twok[nd][0] = pr; iloop(1, 20) { if (twok[nd][i-1] == -1) break; twok[nd][i] = twok[twok[nd][i-1]][i-1]; } unpre[cnt] = nd; pre[nd] = cnt++; for (auto it : adj[nd]) if (it != pr) dfs1(it, nd, dp+1); } ll lca(ll x, ll y) { if (dpt[x] < dpt[y]) swap(x, y); iloop(19, -1) if ((dpt[x] - dpt[y])&(1<<i)) { x = twok[x][i]; } if (x == y) return x; iloop(19, -1) if (twok[x][i] != twok[y][i]) { x = twok[x][i]; y = twok[y][i]; } return twok[x][0]; } vector<ll> ans; ll dfs2(ll nd, ll pr) { ll cv = ccnt[nd]; for (auto it : adj[nd]) if (it != pr) cv += dfs2(it, nd); if (cv >= t) ans.push_back(ced[nd]); return cv; } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); memset(twok, -1, sizeof(twok)); cin >> n >> m >> t; ll t1, t2; iloop(1, n) { cin >> t1 >> t2; t1--, t2--; a[i] = {t1, t2}; adj[t1].push_back(t2); adj[t2].push_back(t1); } dfs1(0, -1, 0); iloop(1, n) { if (dpt[a[i].first] < dpt[a[i].second]) swap(a[i].first, a[i].second); ced[a[i].first] = i; } iloop(0, m) { cin >> g; vector<ll> v; jloop(0, g) { cin >> t1; t1--; ccnt[t1]++; v.push_back(pre[t1]); } sort(v.begin(), v.end()); jloop(0, g) ccnt[lca(unpre[v[j]], unpre[v[(j+1)%g]])]--; } dfs2(0, -1); if (ans.size()) sort(ans.begin(), ans.end()); cout << ans.size() << "\n"; for (auto it : ans) cout << it << " "; }