#include <bits/stdc++.h>
#define fr(i, n, m) for(int i = (n); i < (m); i ++)
#define pb push_back
#define st first
#define nd second
#define pq priority_queue
#define all(x) begin(x), end(x)
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
const ll inf = 1e18;
const ll mod = 1000000007;
const ld eps = 1e-13;
const ld pi = 3.14159265359;
mt19937 _rand(time(NULL));
clock_t timer = clock();
const int mxn = 2e5;
vector<pii> g[mxn];
int sparse[mxn][20];
int depth[mxn];
int pos[mxn];
int sz[mxn];
int par[mxn];
int tmp = 0;
void dfs0(int u, int p){
pos[u] = tmp ++;
sparse[u][0] = p;
fr(i, 1, 20) sparse[u][i] = sparse[sparse[u][i-1]][i-1];
sz[u] = 1;
for(auto e : g[u]){
if(e.st == p) continue;
depth[e.st] = depth[u] + 1;
par[e.st] = e.nd;
dfs0(e.st, u);
sz[u] += sz[e.st];
}
}
int lca(int a, int b){
int d = min(depth[a], depth[b]);
for(int i = 19; i >= 0; i --){
if(depth[a]-(1<<i) >= d) a = sparse[a][i];
if(depth[b]-(1<<i) >= d) b = sparse[b][i];
}
if(a == b) return a;
for(int i = 19; i >= 0; i --){
if(sparse[a][i] != sparse[b][i]){
a = sparse[a][i];
b = sparse[b][i];
}
}
return sparse[a][0];
}
int memo[mxn][20];
void update(int u, int p){
for(int i = 19; i >= 0; i --){
if(depth[u]-(1<<i) >= depth[p]){
memo[u][i] += 1;
u = sparse[u][i];
}
}
}
int n, m, k;
void restore(){
for(int i = 19; i >= 1; i --){
fr(u, 0, n){
memo[u][i-1] += memo[u][i];
memo[sparse[u][i-1]][i-1] += memo[u][i];
}
}
}
void solve(){
cin >> n >> m >> k;
fr(i, 0, n-1){
int u, v;
cin >> u >> v;
--u, --v;
g[u].pb({v, i+1});
g[v].pb({u, i+1});
}
dfs0(0, 0);
fr(q, 0, m){
int s;
cin >> s;
int a[s];
fr(i, 0, s){
cin >> a[i];
-- a[i];
}
sort(a, a + s, [](const int &i, const int &j){
return pos[i] < pos[j];
});
vector<int> v;
fr(i, 0, s) v.pb(a[i]);
fr(i, 0, s-1){
v.pb(lca(a[i], a[i+1]));
}
bool root = false;
sort(all(v));
if(v[0] == 0) root = true;
v.erase(unique(all(v)), v.end());
sort(all(v), [](const int &i, const int &j){
return pos[i] < pos[j];
});
stack<int> S;
S.push(0);
for(auto u : v){
if(u == 0) continue;
while(pos[S.top()]+sz[S.top()] <= pos[u]) S.pop();
if(S.top() != 0 || root) update(u, S.top());
S.push(u);
}
}
restore();
vector<int> sol;
fr(i, 1, n){
if(memo[i][0] >= k){
sol.pb(par[i]);
}
}
sort(all(sol));
cout<<sol.size()<<endl;
for(auto u : sol) cout<<u<<' ';
cout<<endl;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
solve();
}
