#include <bits/stdc++.h>
using namespace std;
const int def = 1e5+1;
const int k = 18;
int f[def][k];
void solve(){
int n, m, k;
cin >> n >> m >> k;
vector<vector<int>> edg(n);
map<pair<int, int>, int> mp;
for (int i = 0; i < n - 1; i++){
int u, v;
cin >> u >> v;
u--; v--;
edg[u].push_back(v);
edg[v].push_back(u);
mp[{u, v}] = mp[{v, u}] = i + 1;
}
for (int i = 0; i < n; i++) for (int j = 0; j < k; j++)
f[i][j] = -1;
vector<int> order(n, 0), h(n, 0);
int t = 0;
auto dfs = [&](int u, int pre, auto&& dfs) -> void{
order[u] = t++;
for (int v : edg[u]){
if (v == pre)
continue;
f[v][0] = u;
h[v] = h[u] + 1;
dfs(v, u, dfs);
}
};
dfs(0, -1, dfs);
for (int j = 1; j < k; j++) for (int i = 0; i < n; i++){
int p = f[i][j - 1];
if (p != -1)
f[i][j] = f[p][j - 1];
}
auto lca = [&](int u, int v) -> int{
if (h[u] < h[v])
swap(u, v);
for (int j = k - 1; j >= 0; j--){
if (f[u][j] != -1 && h[f[u][j]] >= h[v])
u = f[u][j];
}
if (u == v)
return u;
for (int j = k - 1; j >= 0; j--){
if (f[u][j] != -1 && f[v][j] != -1 && f[u][j] != f[v][j]){
u = f[u][j];
v = f[v][j];
}
}
return f[u][0];
};
vector<int> add(n, 0);
for (int i = 0; i < m; i++){
int s;
cin >> s;
vector<int> node;
for (int j = 0; j < s; j++){
int u; cin >> u;
node.push_back(u - 1);
}
sort(node.begin(), node.end(), [&](int a, int b){ return order[a] < order[b]; });
int m = node.size();
for (int j = 0; j < m - 1; j++)
node.push_back(lca(node[j], node[j + 1]));
sort(node.begin(), node.end(), [&](int a, int b){ return order[a] < order[b]; });
node.erase(unique(node.begin(), node.end()), node.end());
for (int j = 1; j < m; j++){
int u = lca(node[j], node[j - 1]), v = node[j];
add[u]--;
add[v]++;
}
}
vector<int> res;
auto get = [&](int u, int pre, auto&& get) -> void{
for (int v : edg[u]){
if (v == pre)
continue;
get(v, u, get);
add[u] += add[v];
}
if (add[u] >= k && pre != -1)
res.push_back(mp[{u, pre}]);
};
get(0, -1, get);
cout << res.size() << endl;
sort(res.begin(), res.end());
for (int i = 0; i < res.size(); i++)
cout << res[i] << ' ';
}
main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
if (ifstream("input.txt").good()){
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
}
int t = 1;
while (t--){
solve();
cout << "\n";
}
}
