#include <bits/stdc++.h>
using namespace std;
#define pii pair <int , int>
#define F first
#define S second
const int N = 2e5 + 10, LOG = 20;
int h[N], par[N][LOG], cnt[N], val[N], st[N], timer = 0;
vector <pii> g[N];
void dfs(int v, int pr = 0)
{
h[v] = h[pr] + 1;
st[v] = timer++;
par[v][0] = pr;
for (int i = 1; i < LOG; i++) par[v][i] = par[par[v][i - 1]][i - 1];
for (auto p : g[v]) if (p.F != pr) dfs(p.F, v);
}
int getpar(int v, int height)
{
for (int i = 0; i < LOG; i++) if (height & (1 << i)) v = par[v][i];
return v;
}
int LCA(int u, int v)
{
if (h[v] < h[u]) swap(u, v);
v = getpar(v, h[v] - h[u]);
if (u == v) return v;
for (int i = LOG - 1; i >= 0; i--) if (par[v][i] != par[u][i]) v = par[v][i], u = par[u][i];
return par[v][0];
}
int solve(int v, int pr = 0, int ID = 0)
{
int VAL = val[v];
for (auto p : g[v]) if (p.F != pr) {
int u = p.F, id = p.S;
VAL += solve(u, v, id);
}
return cnt[ID] = VAL;
}
bool cmp(int i, int j) {return st[i] < st[j];}
int32_t main()
{
ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
int n, k, q; cin >> n >> q >> k;
for (int i = 1; i < n; i++) {
int u, v; cin >> u >> v;
g[u].push_back({v, i});
g[v].push_back({u, i});
}
dfs(1);
while (q--) {
int s; cin >> s;
vector <int> vec;
for (int i = 0; i < s; i++) {
int u; cin >> u; val[u]++;
vec.push_back(u);
}
sort(vec.begin(), vec.end(), cmp);
for (int i = 0; i < s - 1; i++) {
val[LCA(vec[i], vec[i + 1])]--;
}
val[LCA(vec[0], vec[s - 1])]--;
}
solve(1);
vector <int> ans;
for (int i = 1; i < n; i++) if (cnt[i] >= k) ans.push_back(i);
cout << ans.size() << "\n";
for (int i : ans) cout << i << " ";
cout << "\n";
return 0;
}
