#include <iostream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <numeric>
#include <cstring>
#include <string>
#include <cmath>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <map>
using namespace std;
#define ll long long
#define ull unsigned long long
#define f first
#define s second
#define PF push_front
#define PB push_back
#define MP make_pair
#define max(a, b) ((a > b)? a : b)
#define min(a, b) ((a < b)? a : b)
#define max3(a, b, c) max(max(a, b), c)
#define min3(a, b, c) min(min(a, b), c)
const int N = 1e5 + 5;
const int M = 1e9 + 7;
const int inf = 0x3f3f3f3f;
const ll int INF = 1e18;
struct BIT {
int sz;
vector<int> tree;
BIT(int n) : sz(n+1), tree(n+1, 0) {};
void add(int pos, int val){
for(; pos < sz; pos += pos&-pos) tree[pos] += val;
}
int sum(int pos){
int ans = 0;
for(; pos >= 1; pos -= pos&-pos) ans += tree[pos];
return ans;
}
};
vector<vector<int>> adj(N, vector<int>()), par(19, vector<int>(N));
vector<int> to(N), tin(N), tout(N);
map<pair<int, int>, int> ind;
int timer = 1;
void dfs(int cur, int prev){
tin[cur] = timer++;
for(int child : adj[cur]){
if(child == prev) continue;
to[child] = cur;
dfs(child, cur);
}
tout[cur] = timer++;
}
bool isAncestor(int anc, int child){
return (tin[anc] <= tin[child] && tout[anc] >= tout[child]);
}
int get_lca(int a, int b){
if(isAncestor(b, a)) return b;
int lca = a, cur = b;
for(int i = 18; i >= 0; i--){
int next_cur = par[i][cur];
if(isAncestor(next_cur, a)){
lca = next_cur;
}else {
cur = next_cur;
}
}
return lca;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
// ifstream cin();
// ofstream cout();
int n, m, k;
cin >> n >> m >> k;
for(int i = 1; i <= n-1; i++){
int a, b;
cin >> a >> b;
ind[MP(a, b)] = i;
ind[MP(b, a)] = i;
adj[a].PB(b);
adj[b].PB(a);
}
to[1] = 1;
dfs(1, -1);
BIT bit(n*2);
for(int i = 1; i <= n; i++) par[0][i] = to[i];
for(int i = 1; i < 19; i++){
for(int j = 1; j <= n; j++){
par[i][j] = par[i-1][par[i-1][j]];
}
}
for(int i = 0; i < m; i++){
int num;
cin >> num;
vector<int> query(num);
for(int j = 0; j < num; j++) cin >> query[j];
sort(query.begin(), query.end(), [](int &a, int &b){return tin[a] < tin[b];});
query.PB(query[0]);
for(int j = 0; j < num; j++){
int lca = get_lca(query[j], query[j+1]);
bit.add(tin[query[j]], 1);
bit.add(tin[query[j+1]], 1);
bit.add(tin[lca], -2);
}
}
vector<int> ans;
for(int i = 2; i <= n; i++){
if(bit.sum(tout[i]) - bit.sum(tin[i]-1) >= 2*k){
ans.PB(ind[MP(i, to[i])]);
}
}
sort(ans.begin(), ans.end());
cout << ans.size() << endl;
for(int i : ans) cout << i << ' ';
}
