#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 1e5 + 2;
const int inf = 1e9;
vector<array<int, 2>> g[N], ch[N];
vector<int> a[N], st[N], ans;
int par[N][17], in[N], out[N], tsz, k;
struct Bit {
int bit[N];
void Add(int x, int v) {
for (; x < N; x += x & (-x)) bit[x] += v;
}
int Get(int x) {
int ans = 0;
for (; x > 0; x -= x & (-x)) ans += bit[x];
return ans;
}
}f;
void Dfs(int s, int e) {
in[s] = ++tsz;
par[s][0] = e;
for (int i = 1; i < 17; i++) par[s][i] = par[par[s][i - 1]][i - 1];
for (auto u : g[s]) {
if (u[0] == e) continue;
Dfs(u[0], s);
}
out[s] = tsz;
}
bool Ancestor(int u, int v) {
return in[u] <= in[v] && out[v] <= out[u];
}
int Lca(int u, int v) {
if (Ancestor(u, v)) return u;
if (Ancestor(v, u)) return v;
for (int i = 16; i >= 0; i--) {
if (par[u][i] && !Ancestor(par[u][i], v)) u = par[u][i];
}
return par[u][0];
}
void Solve(int s, int e) {
for (int u : st[s]) f.Add(in[a[u][0]], 1);
for (auto u : ch[s]) {
f.Add(in[a[u[0]][u[1]]], -1);
if (u[1] < a[u[0]].size() - 1) f.Add(in[a[u[0]][u[1] + 1]], 1);
}
for (auto u : g[s]) {
if (u[0] == e) continue;
if (f.Get(out[u[0]]) - f.Get(in[u[0]] - 1) >= k) ans.push_back(u[1]);
Solve(u[0], s);
}
for (int u : st[s]) f.Add(in[a[u][0]], -1);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int n, s;
cin >> n >> s >> 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, 0);
for (int i = 1; i <= s; i++) {
int sz; cin >> sz;
a[i].resize(sz);
for (int j = 0; j < sz; j++) cin >> a[i][j];
sort(a[i].begin(), a[i].end(), [&] (int ii, int jj) {
return in[ii] < in[jj];
});
int lca = a[i][0];
for (int j = 1; j < sz; j++) lca = Lca(lca, a[i][j]);
st[lca].push_back(i);
for (int j = 0; j < sz; j++) ch[a[i][j]].push_back({i, j});
}
Solve(1, 0);
sort(ans.begin(), ans.end());
cout << ans.size() << en;
for (int u : ans) cout << u << sp;
cout << en;
return 0;
}
