#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define pb push_back
#define ff first
#define ss second
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, m, k; cin>>n>>m>>k;
vector<int> g[n + 1];
vector<pii> ed;
for (int i = 1; i < n; i++){
int x, y; cin>>x>>y;
g[x].pb(y);
g[y].pb(x);
ed.pb({x, y});
}
vector<int> sz(n + 1), h(n + 1), p(n + 1), d(n + 1);
function<void(int, int)> fill = [&](int v, int pr){
p[v] = pr;
sz[v] = 1;
for (int i: g[v]){
if (i == pr) continue;
d[i] = d[v] + 1;
fill(i, v);
if (sz[i] > sz[h[v]]){
h[v] = i;
}
sz[v] += sz[i];
}
};
fill(1, 0);
vector<int> pos(n + 1), head(n + 1);
int timer = 0;
function<void(int, int)> fill_hld = [&](int v, int k){
pos[v] = ++timer;
head[v] = k;
if (h[v]) fill_hld(h[v], k);
for (int i: g[v]){
if (pos[i]) continue;
fill_hld(i, i);
}
};
fill_hld(1, 1);
vector<pii> all;
auto add = [&](int x, int y){
while (true){
if (head[x] == head[y]){
if (d[x] > d[y]) swap(x, y);
if (pos[x] < pos[y]){
all.pb({pos[x] + 1, pos[y]});
}
break;
}
else {
if (d[head[x]] > d[head[y]]) swap(x, y);
all.pb({pos[head[y]], pos[y]});
y = p[head[y]];
}
}
};
vector<int> pr(n + 2);
while (m--){
int s; cin>>s;
vector<int> a(s + 1);
for (int i = 1; i <= s; i++){
cin>>a[i];
}
all.clear();
for (int i = 1; i < s; i++){
add(a[i], a[i + 1]);
}
sort(all.begin(), all.end());
int L = all[0].ff, R = all[0].ss;
for (auto [l, r]: all){
if (l <= R){
R = max(R, r);
continue;
}
pr[L]++; pr[R + 1]--;
L = l; R = r;
}
pr[L]++; pr[R + 1]--;
}
vector<int> inv(n + 1);
for (int i = 1; i <= n; i++) inv[pos[i]] = i;
vector<int> ind(n + 1);
for (int i = 0; i < ed.size(); i++){
auto [x, y] = ed[i];
if (d[x] > d[y]) swap(x, y);
ind[y] = i + 1;
}
vector<int> out;
for (int i = 1; i <= n; i++){
pr[i] += pr[i - 1];
if (pr[i] >= k){
int j = inv[i];
out.pb(ind[j]);
}
}
sort(out.begin(), out.end());
cout<<out.size()<<"\n";
for (int i: out){
cout<<i<<" ";
}
cout<<"\n";
}
