#include<bits/stdc++.h> //:3
using namespace std;
typedef long long ll;
#define all(a) (a).begin(), (a).end()
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define pi pair<long double, long double>
#define sz(x) (int)((x).size())
//#define int long long
const int dx[] = {0, 1, 0, -1};
const int dy[] = {1, 0, -1, 0};
const ll inf = 2e9;
const ll mod = 1e9 + 7;
const int N = 2e5 + 11;
const ll INF64 = 3e18 + 1;
const double eps = 1e-14;
const double PI = acos(-1);
//ifstream in(".in");
//ofstream out(".out");
int n, m, k, dp[N][50], cnt[N], tin[N], tout[N], t;
pi e[N];
vector<int>v[N];
void dfs(int nod, int p){
tin[nod] = ++t;
dp[nod][0] = p;
for(auto it : v[nod]){
if(it == p)continue;
dfs(it, nod);
}
tout[nod] = ++t;
}
void hug(){
for(int i = 1; i <= 20; i++){
for(int j = 1; j <= n; j++){
dp[j][i] = dp[dp[j][i - 1]][i - 1];
}
}
}
bool is_ancestor(int p, int x){
if(tin[p] <= tin[x] && tout[x] <= tout[p]) return 1;
return 0;
}
int lca(int x, int y){
if(is_ancestor(x,y))return x;
if(is_ancestor(y,x))return y;
for(int i = 20; i >= 0; i--){
if(!is_ancestor(dp[x][i], y) && dp[x][i] != 0)x = dp[x][i];
}
return dp[x][0];
}
void dfs2(int nod, int p){
for(auto it : v[nod]){
if(it == p)continue;
dfs2(it, nod);
cnt[nod] += cnt[it];
}
}
void solve(){
cin >> n >> m >> k;
for(int i = 1, x, y; i < n; i++){
cin >> x >> y;
v[x].push_back(y);
v[y].push_back(x);
e[i] = {x, y};
}
dfs(1, 0);
hug();
for(int i = 1, x; i <= m; i++){
cin >> x;
vector<int>V;
for(int j = 1, y; j <= x; j++){
cin >> y;
V.push_back(y);
}
sort(all(V),[](int l, int r){
return (tin[l] < tin[r]);
});
for(int j = 0; j < sz(V); j++){
int x = V[j], y = V[(j + 1) % sz(V)];
cnt[x]++;
cnt[y]++;
cnt[lca(x,y)] -= 2;
}
}
dfs2(1, 0);
vector<int>ans;
for(int i = 1; i < n; i++){
int a = e[i].ff, b = e[i].ss;
if(tin[a] > tin[b])swap(a, b);
if(cnt[b] >= 2*k)ans.push_back(i);
}
cout << sz(ans) << '\n';
for(auto it : ans)cout << it << ' ';
}
int32_t main(){
ios_base :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
//cout << setprecision(6) << fixed;
int T = 1;
//cin >> T;
while(T--){
solve();
}
}
