#include<bits/stdc++.h>
using namespace std;
/*for ordered_set
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<pair<int,int>, null_type,less<pair<int,int>>, rb_tree_tag,tree_order_statistics_node_update>
*/
const long long INFll = (long long) 1e18 + 10;
const int INFii = (int) 1e9 + 10;
typedef long long ll;
typedef int ii;
typedef long double dbl;
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
#define maxn 110000
ii n, m, k, cnt[maxn], bit[maxn], p[maxn][25], ps[maxn], h[maxn];
vector<pair<ii,ii>> edg, g[maxn];
ii tin[maxn], tout[maxn], timer = 1;
void att(ii pos, ii val) {
for(ii i = pos; i <= n; i+= i&-i) {
bit[i]+= val;
}
}
ii qr(ii pos) {
ii val = 0;
for(ii i = pos; i > 0; i-= i&-i) {
val+= bit[i];
}
return val;
}
ii lca(ii u, ii v) {
if(h[u] < h[v]) swap(u,v);
for(ii i = 20; i >= 0; i--) {
if(h[p[u][i]] >= h[v]) {
u = p[u][i];
}
}
if(u == v) {
return u;
}
for(ii i = 20; i >= 0; i--) {
if(p[u][i] != p[v][i]) {
u = p[u][i];
v = p[v][i];
}
}
return p[u][0];
}
void dfst(ii u, ii ant, ii id) {
//.fr = pai .sc = filho
if(u != 1 && edg[id].fr == u) swap(edg[id].fr,edg[id].sc);
tin[u] = timer++;
for(auto V : g[u]) {
ii v = V.fr;
ii id1 = V.sc;
if(v == ant) continue;
dfst(v,u,id1);
}
tout[u] = timer-1;
}
void dfslca(ii u, ii ant, ii id) {
//.fr = pai .sc = filho
if(u != 1 && edg[id].fr == u) swap(edg[id].fr,edg[id].sc);
p[u][0] = ant;
for(ii i = 1; i <= 20; i++) {
p[u][i] = p[p[u][i-1]][i-1];
}
for(auto V : g[u]) {
ii v = V.fr;
ii id1 = V.sc;
if(v == ant) continue;
h[v] = h[u]+1;
dfslca(v,u,id1);
}
}
void dfsps(ii u, ii ant) {
for(auto V : g[u]) {
ii v = V.fr;
if(v == ant) continue;
dfsps(v,u);
ps[u]+= ps[v];
}
}
void solve() {
cin >> n >> m >> k;
for(ii i = 0; i < n-1; i++) {
ii a, b;
cin >> a >> b;
g[a].pb(mp(b,i));
g[b].pb(mp(a,i));
edg.pb(mp(a,b));
}
h[1] = 0;
dfslca(1,1,0);
while(m--) {
ii s; cin >> s;
vector<pair<ii,ii>> vert;
for(ii i = 0; i < s; i++) {
ii u; cin >> u;
vert.pb(mp(tin[u],u));
}
sort(all(vert));
for(ii i = 0; i < s; i++) {
ii u = vert[i].sc;
ii v = vert[(i+1)%s].sc;
ii lc = lca(u,v);
ps[u]++;
ps[v]++;
ps[lc]-= 2;
}
}
dfsps(1,1);
for(ii i = 0; i < n-1; i++) {
ii v = edg[i].sc;
cnt[i] = ps[v]/2;
}
vector<ii> ans;
for(ii i = 0; i < n-1; i++) {
if(cnt[i] >= k) ans.pb(i+1);
}
cout << ans.size() << endl;
for(auto x : ans) cout << x << " ";
cout << endl;
}
int main() {
ios::sync_with_stdio(false); cin.tie(0);
// freopen("in.in", "r", stdin);
//freopen("out.out", "w", stdout);
ii tt = 1;
// cin >> tt;
while(tt--) solve();
}
