#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define endl "\n"
using namespace std;
using namespace __gnu_pbds;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
template <typename T, typename key = less<T>>
using ordered_set = tree<T, null_type, key, rb_tree_tag, tree_order_statistics_node_update>;
struct SegTree
{
ll n;
vector<ll> st;
SegTree(ll sz = 0)
{
n = sz;
st.resize(n << 1, 0);
}
void set(ll i, ll val)
{
st[i + n - 1] = val;
}
void build()
{
for (ll i = n - 1; i >= 1; i--)
st[i] = st[i << 1] + st[i << 1 | 1];
}
void modify(ll p, ll val)
{
for (st[p += n - 1] += val; p > 1; p >>= 1)
st[p >> 1] = st[p] + st[p ^ 1];
}
ll query(ll l, ll r)
{
ll ans = 0;
for (l += n - 1, r += n; l < r; l >>= 1, r >>= 1)
{
if (l & 1)
ans += st[l++];
if (r & 1)
ans += st[--r];
}
return ans;
}
};
const ll N = 1e5 + 5;
vector<pair<ll, ll>> g[N];
ll ind[N], d[N], f[N], timer = 0, cnt[N];
pair<ll, ll> reald[N];
void dfs(ll v, ll par = 0)
{
d[v] = ++timer;
for (auto [to, id] : g[v])
if (to != par)
ind[to] = id, dfs(to, v);
f[v] = timer;
reald[d[v]] = make_pair(f[v], v);
}
void solve()
{
ll n, m, k;
cin >> n >> m >> k;
k = m - k;
for (ll i = 1; i < n; i++)
{
ll a, b;
cin >> a >> b;
g[a].push_back(make_pair(b, i));
g[b].push_back(make_pair(a, i));
}
dfs(1);
vector<pair<ll, ll>> segs, seg1;
while (m--)
{
ll sz;
cin >> sz;
vector<ll> v(sz);
for (ll &i : v)
cin >> i, i = d[i];
sort(v.begin(), v.end());
ll last = 0;
for (ll i = 0; i < v.size(); i++)
{
if (last + 1 <= v[i] - 1)
segs.push_back(make_pair(last + 1, v[i] - 1));
last = v[i];
}
if (last + 1 <= n)
segs.push_back(make_pair(last + 1, n));
seg1.push_back(make_pair(v.front(), v.back()));
}
sort(segs.begin(), segs.end());
sort(seg1.begin(), seg1.end(), greater());
ll ptr = 0;
SegTree st(n);
for (ll i = 1; i <= n; i++)
{
while (ptr < segs.size() and segs[ptr].first <= i)
st.modify(segs[ptr].second, 1), ptr++;
cnt[reald[i].second] += st.query(reald[i].first, n);
// for (auto [l, r] : segs) cnt[reald[i].second] += l <= i and reald[i].first <= r;
}
st = SegTree(n);
ptr = 0;
for (ll i = n; i >= 1; i--)
{
while (ptr < seg1.size() and seg1[ptr].first >= i)
st.modify(seg1[ptr].second, 1), ptr++;
cnt[reald[i].second] += st.query(1, reald[i].first);
// for (auto [l, r] : seg1) cnt[reald[i].second] += i <= l and r <= reald[i].first;
}
// for (ll i = 1; i <= n; i++) cout << d[i] << " " << f[i] << endl;
vector<ll> ans;
for (ll i = 2; i <= n; i++)
if (cnt[i] <= k)
ans.push_back(ind[i]);
sort(ans.begin(), ans.end());
cout << ans.size() << endl;
for (ll i : ans)
cout << i << " ";
cout << endl;
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
ll t = 1;
// precomp();
// cin >> t;
for (ll cs = 1; cs <= t; cs++)
solve();
// cerr << "\nTime elapsed: " << clock() * 1000.0 / CLOCKS_PER_SEC << " ms\n";
}
