#include <bits/stdc++.h>
using namespace std;
#include <bits/stdc++.h>
using namespace std;
const int MXN = 100001;
const int lg = 19;
int up[lg][MXN], tin[MXN], tout[MXN], chosen[MXN];
array<int, 2> edges[MXN];
vector<int> adj[MXN];
int timer = 0;
int tree[MXN];
int n, m, k;
void upd(int pos, int val){
for(; pos <= n; pos += (pos&(-pos)))
tree[pos] += val;
}
int query(int idx){
int sum = 0;
for(; idx > 0; idx -= (idx&(-idx)))
sum += tree[idx];
return sum;
}
int query(int l, int r){
return query(r) - query(l-1);
}
void dfs(int node = 1, int par = 0){
tin[node] = ++timer;
up[0][node] = par;
for(int i = 1; i < lg; i++)
up[i][node] = up[i-1][up[i-1][node]];
for(int v : adj[node]){
if(v == par)
continue;
dfs(v, node);
}
tout[node] = timer;
}
inline bool isAncestor(int u, int v) { return tin[u] <= tin[v] && tout[u] >= tout[v]; }
int lca(int u, int v){
if(isAncestor(u, v))
return u;
if(isAncestor(v, u))
return v;
for(int i = lg-1; i >= 0; --i)
if(up[i][u] && !isAncestor(up[i][u], v))
u = up[i][u];
return up[0][u];
}
int32_t main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> m >> k;
for(int i = 1; i < n; i++){
int u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
edges[i] = {u, v};
}
dfs();
while(m--){
int s;
cin >> s;
for(int i = 0; i < s; i++)
cin >> chosen[i];
sort(chosen, chosen + s, [&](int a, int b){
return tin[a] < tin[b];
});
chosen[s] = chosen[0];
for(int i = 0; i < s; i++){
int l = lca(chosen[i], chosen[i+1]);
upd(tin[chosen[i]], 1);
upd(tin[chosen[i+1]], 1);
upd(tin[l], -2);
}
}
vector<int> ans;
for(int i = 1; i < n; i++){
int u = edges[i][0], v = edges[i][1];
if(tin[u] > tin[v])
swap(u, v);
if(query(tin[v], tout[v]) >= 2*k)
ans.push_back(i);
}
cout << ans.size() << '\n';
for(int i : ans)
cout << i << ' ';
return 0;
}
