#include <bits/stdc++.h>
using namespace std;
const int N = (1 << 18);
int n, m, k;
int st[N], en[N];
vector<int> deps[N], ans;
int t = 3, r, r2;
int L[N], R[N];
vector<pair<int, int>> adj[N];
int er[N];
vector<pair<pair<int, int>, int>> eve, eve2;
int an1[N], an2[N];
int bit[N][2];
void add(int x, int idx = 0, int val = 1)
{
for (; x < N; x += x & -x)
bit[x][idx] += val;
}
int get(int x, int idx = 0, int val = 1)
{
int ret = 0;
for (; x; x -= x & -x)
ret += bit[x][idx];
return ret;
}
void solve1()
{
sort(eve.begin(), eve.end(), [&](pair<pair<int, int>, int> a, pair<pair<int, int>, int> b) {
if (a.first.first == b.first.first)
{
return a.second < b.second;
}
return a.first < b.first;
});
vector<int> ends;
map<int, int> qu;
map<int, int> frs;
for (auto u : eve)
{
if (u.second == 0)
qu[u.first.second] = u.first.first;
else if (u.second == 1)
frs[u.first.second] = u.first.first;
else if (u.second == 2)
{
ends.push_back(frs[u.first.second]);
add((frs[u.first.second]));
}
else
an1[u.first.second] = get(N - 1) - get(qu[u.first.second] - 1);
}
}
void solve2()
{
memset(bit, 0, sizeof bit);
sort(eve2.begin(), eve2.end(), [&](pair<pair<int, int>, int> a, pair<pair<int, int>, int> b) {
if (a.first.first == b.first.first)
{
return a.second < b.second;
}
return a.first < b.first;
});
vector<int> ends;
map<int, int> qu;
map<int, int> frs;
for (auto u : eve2)
{
if (u.second == 1)
qu[u.first.second] = u.first.first;
else if (u.second == 0)
{
frs[u.first.second] = u.first.first;
add(u.first.first, 1, 1);
}
else if (u.second == 3)
{
ends.push_back(frs[u.first.second]);
add(frs[u.first.second], 1, -1);
}
else
{
an2[u.first.second] = get(qu[u.first.second], 1);
}
}
}
void dfz(int x, int p)
{
st[x] = ++t;
for (auto u : adj[x])
{
if (u.first == p)
continue;
dfz(u.first, x);
}
en[x] = ++t;
return;
}
void dfs0(int x, int p)
{
for (auto u : adj[x])
{
if (u.first == p)
continue;
int cnt = m;
er[u.second] = u.first;
eve.push_back({{st[u.first], u.second}, 0});
eve.push_back({{en[u.first], u.second}, 3});
eve2.push_back({{st[u.first], u.second}, 1});
eve2.push_back({{en[u.first], u.second}, 2});
dfs0(u.first, x);
}
return;
}
void dfs(int x, int p)
{
for (auto u : adj[x])
{
if (u.first == p)
continue;
int cnt = m;
cnt -= an1[u.second];
cnt -= an2[u.second];
if (cnt >= k)
{
ans.push_back(u.second + 1);
}
dfs(u.first, x);
}
return;
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
//freopen("in.in", "r", stdin);
cin >> n >> m >> k;
for (int i = 0; i < n - 1; i++)
{
int u, v;
cin >> u >> v;
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
dfz(1, 1);
for (int i = 0; i < m; i++)
{
int x;
cin >> x;
vector<int> vec;
for (int j = 0; j < x; j++)
{
int t;
cin >> t;
deps[i].push_back(t);
vec.push_back(st[t]);
}
sort(vec.begin(), vec.end());
int l = 1;
for (auto u : vec)
{
if (u > l && l + 1 <= u - 1)
{
eve2.push_back({{l + 1, r2}, 0});
eve2.push_back({{u - 1, r2}, 3});
r2++;
}
l = u;
}
L[i] = vec[0];
R[i] = vec.back();
eve.push_back({{L[i], r}, 1});
eve.push_back({{R[i], r}, 2});
eve2.push_back({{l + 1, r2}, 0});
eve2.push_back({{N - 1, r2}, 3});
r2++;
r++;
}
dfs0(1, 1);
solve1();
solve2();
dfs(1, 1);
cout << (int)ans.size() << "\n";
sort(ans.begin(), ans.end());
for (auto u : ans)
{
cout << u << " ";
}
return 0;
}
