#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <bits/stdc++.h>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef pair<ldb,ldb> pdd;
#define ff(i,a,b) for(int i = a; i <= b; i++)
#define fb(i,b,a) for(int i = b; i >= a; i--)
#define trav(a,x) for (auto& a : x)
#define sz(a) (int)(a).size()
#define fi first
#define se second
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
// os.order_of_key(k) the number of elements in the os less than k
// *os.find_by_order(k) print the k-th smallest number in os(0-based)
const int mod = 1000000007;
const int inf = 1e9 + 5;
const int mxN = 100005;
int n, q, k;
vector<pii> g[mxN];
int timer = 0;
int in[mxN];
int out[mxN];
int deda[mxN][20];
void dfs1(int v, int p){
in[v] = ++timer;
deda[v][0] = p; ff(i,1,19)deda[v][i] = deda[deda[v][i - 1]][i - 1];
for(auto c : g[v]){
if(c.fi != p){
dfs1(c.fi, v);
}
}
out[v] = timer;
}
bool predak(int x, int y){
return in[x] <= in[y] && in[y] <= out[x];
}
int LCA(int x, int y){
if(predak(x, y))return x;
if(predak(y, x))return y;
fb(i,19,0)if(deda[x][i] != 0 && !predak(deda[x][i], y))x = deda[x][i];
return deda[x][0];
}
int A[mxN];
bool cmp(int s1, int s2){
return in[s1] < in[s2];
}
vector<int> add[mxN];
vector<int> rem[mxN];
map<int,int> dt[mxN];
void comb(int x, int y){
if(sz(dt[x]) < sz(dt[y]))swap(dt[x], dt[y]);
for(auto c : dt[y]){
dt[x][c.fi] += c.se;
}
}
int kol[mxN];
void dfs2(int v, int p){
for(auto c : g[v]){
int u = c.fi;
int i = c.se;
if(u != p){
dfs2(u, v);
kol[i] = sz(dt[u]);
comb(v, u);
}
}
for(auto c : add[v]){
dt[v][c] += 1;
}
for(auto c : rem[v]){
dt[v][c] -= 1;
if(dt[v][c] == 0)dt[v].erase(c);
}
}
int main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n >> q >> k;
ff(i,1,n - 1){
int u, v;
cin >> u >> v;
g[u].pb({v, i});
g[v].pb({u, i});
}
dfs1(1, 0);
ff(i,1,q){
int len;
cin >> len;
ff(j,1,len)cin >> A[j];
sort(A + 1, A + len + 1, cmp);
ff(j,2,len){
int X = A[j - 1];
int Y = A[j];
int Z = LCA(X, Y);
if(Z != Y){
add[Y].pb(i);
rem[Z].pb(i);
}
if(Z != X){
add[X].pb(i);
rem[Z].pb(i);
}
}
}
dfs2(1, 0);
vector<int> res;
ff(i,1,n - 1)if(kol[i] >= k)res.pb(i);
cout << sz(res) << '\n';
for(auto c : res)cout << c << " ";
cout << '\n';
return 0;
}
/*
6 3 2
1 3
2 3
3 4
6 4
4 5
4 1 3 2 5
2 6 3
2 3 2
// probati bojenje sahovski
*/
