#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#define int long long int
const int LOG = 22;
const int MAX = 5e5 + 10;
const int INF = 0x3f3f3f3f;
int n, m, k, f[MAX], dp[MAX][LOG], h[MAX], tin[MAX], a[MAX], timer;
vector<pair<int, int>> adj[MAX];
vector<int> ids;
void dfs(int u, int p){
tin[u] = ++timer;
dp[u][0] = p; h[u] = h[p] + 1;
for(int i = 1; i < LOG; i++)
dp[u][i] = dp[ dp[u][i - 1] ][i - 1];
for(auto [v, id] : adj[u]){
if(v == p) continue;
dfs(v, u);
}
}
int lca(int u, int v){
if(h[u] < h[v]) swap(u, v);
int jump = h[u] - h[v];
for(int j = LOG - 1; j >= 0; j--)
if(jump & (1 << j)) u = dp[u][j];
if(u == v) return v;
for(int j = LOG - 1; j >= 0; j--)
if(dp[u][j] != dp[v][j]) u = dp[u][j], v = dp[v][j];
return dp[u][0];
}
void calcResp(int u, int p, int id){
for(auto [v, nx] : adj[u]){
if(v == p) continue;
calcResp(v, u, nx);
f[u] += f[v];
}
if(f[u] >= k * 2 && id != 0)
ids.push_back(id);
}
int32_t main(void){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> m >> k;
for(int i = 1; i < n; i++){
int u, v; cin >> u >> v;
adj[u].emplace_back(v, i);
adj[v].emplace_back(u, i);
}
dfs(1, 0);
for(int i = 1; i <= m; i++){
int n; cin >> n;
for(int i = 1; i <= n; i++)
cin >> a[i];
sort(a + 1, a + n + 1, [&](int i, int j){
return tin[i] < tin[j];
});
a[n + 1] = a[1];
for(int i = 1; i <= n; i++) {
f[a[i]]++; f[a[i + 1]]++;
f[lca(a[i], a[i + 1])] -= 2;
}
}
calcResp(1, 0, 0);
cout << ids.size() << '\n';
sort(ids.begin(), ids.end());
for(auto x : ids) cout << x << ' ';
}
