#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#define int int64_t
using namespace std;
int log2(int n)
{
int r = 0;
for (; n; n /= 2) r++;
return r;
}
struct tree
{
int n;
vector<vector<int>> adjlist;
vector<vector<int>> st;
vector<vector<int>> en;
vector<int> res;
set<int>* smldfs(int curr, int par)
{
set<int>* rs = new set<int>(st[curr].begin(), st[curr].end());
for (auto next : adjlist[curr])
{
if (next == par) continue;
set<int>* ot = smldfs(next, curr);
if (ot->size() > rs->size()) swap(ot, rs);
for (auto i : (*ot))
{
rs->insert(i);
}
}
for (auto i : en[curr])
{
rs->erase(i);
}
res[curr] = rs->size();
return rs;
}
vector<vector<int>> table;
vector<int> lvl;
int logn;
void dfs(int curr, int par, int lv)
{
lvl[curr] = lv;
table[0][curr] = par;
for (auto next : adjlist[curr]) if (next != par) dfs(next, curr, lv + 1);
}
void prelca()
{
logn = log2(n) + 1;
table.resize(logn, vector<int>(n));
lvl.resize(n);
dfs(0, -1, 0);
for (int i = 1; i < logn; i++)
{
for (int j = 0; j < n; j++)
{
table[i][j] = (table[i - 1][j] == -1 ? -1 : table[i - 1][table[i - 1][j]]);
}
}
}
int lca(int a, int b)
{
if (lvl[a] < lvl[b]) swap(a, b);
int ld = lvl[a] - lvl[b];
for (int j = 0; j < logn; j++)
{
if (ld & (1<<j)) a = table[j][a];
}
if (a == b) return a;
for (int j = logn - 1; j >= 0; j--)
{
if (table[j][a] != table[j][b])
{
a = table[j][a];
b = table[j][b];
}
}
return table[0][a];
}
};
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, m, k;
cin >> n >> m >> k;
tree t;
t.n = n;
t.adjlist.resize(n);
vector<pair<int,int>> edges;
for (int i = 0; i < n - 1; i++)
{
int a, b;
cin >> a >> b;
a--; b--;
edges.emplace_back(a, b);
t.adjlist[a].push_back(b);
t.adjlist[b].push_back(a);
}
t.prelca();
t.st.resize(n);
t.en.resize(n);
for (int i = 0; i < m; i++)
{
int c;
cin >> c;
int l = -1;
for (int j = 0; j < c; j++)
{
int a;
cin >> a;
a--;
t.st[a].push_back(i);
if (l == -1) l = a;
else l = t.lca(l, a);
}
t.en[l].push_back(i);
}
t.res.resize(n);
t.smldfs(0, -1);
vector<int> sol;
for (int i = 0; i < n - 1; i++)
{
auto e = edges[i];
int a = (t.lvl[e.first] > t.lvl[e.second] ? e.first : e.second);
if (t.res[a] >= k) sol.push_back(i + 1);
}
cout << sol.size() << "\n";
for (auto i : sol) cout << i << " ";
cout << "\n";
}
