#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
const int N = 100000;
int ij[N - 1];
vector<int> eh[N];
int ta[N], tb[N];
int dd[N], pp[N], qq[N];
int ii[N], ft[N], kk[N];
void dfs(int p, int i, int d) {
static int t;
ta[i] = t++;
dd[i] = d++;
pp[i] = qq[i] = p;
if (dd[p] - dd[qq[p]] == dd[qq[p]] - dd[qq[qq[p]]])
qq[i] = qq[qq[p]];
for (int h : eh[i]) {
int j = i ^ ij[h];
if (j != p)
dfs(i, j, d);
}
tb[i] = t;
}
void update(int i, int n, int a) {
for ( ; i < n; i |= i + 1)
ft[i] += a;
}
int query(int i) {
int a = 0;
for ( ; i >= 0; i &= i + 1, i--)
a += ft[i];
return a;
}
int lca(int i, int j) {
if (dd[i] < dd[j])
swap(i, j);
while (dd[i] > dd[j])
if (dd[qq[i]] > dd[j])
i = qq[i];
else
i = pp[i];
while (i != j)
if (qq[i] != qq[j])
i = qq[i], j = qq[j];
else
i = pp[i], j = pp[j];
return i;
}
bool check(int i) {
return query(tb[i] - 1) - query(ta[i] - 1);
}
int search(int i) {
while (!check(i))
if (!check(qq[i]))
i = qq[i];
else
i = pp[i];
return i;
}
int dfs_(int h_, int i, int k_) {
int k = kk[i];
for (int h : eh[i])
if (h != h_)
k += dfs_(h, i ^ ij[h], k_);
if (i && k >= k_)
ij[h_] = -1;
return k;
}
int main() {
ios_base::sync_with_stdio(false), cin.tie(NULL);
int n, q, k; cin >> n >> q >> k;
for (int h = 0; h < n - 1; h++) {
int i, j; cin >> i >> j, i--, j--;
ij[h] = i ^ j;
eh[i].push_back(h);
eh[j].push_back(h);
}
dfs(0, 0, 0);
while (q--) {
int m; cin >> m;
for (int h = 0; h < m; h++)
cin >> ii[h], ii[h]--;
int a = ii[0];
update(ta[a], n, 1);
for (int h = 1; h < m; h++) {
int i = ii[h];
kk[a]++, kk[a = lca(a, i)]--;
kk[i]++, kk[search(i)]--;
update(ta[i], n, 1);
}
for (int h = 0; h < m; h++)
update(ta[ii[h]], n, -1);
}
dfs_(-1, 0, k);
int x = 0;
for (int h = 0; h < n - 1; h++)
if (ij[h] == -1)
x++;
cout << x << '\n';
for (int h = 0; h < n - 1; h++)
if (ij[h] == -1)
cout << h + 1 << ' ';
cout << '\n';
return 0;
}
