/**
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*/
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <queue>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cassert>
#define F first
#define S second
#define endl '\n'
#define deb(x) cout<<#x<<' '<<x<<endl;
#define pb push_back
using namespace __gnu_pbds;
using namespace std;
typedef tree<
int,
null_type,
less<int>,
rb_tree_tag,
tree_order_statistics_node_update>
ordered_set;
/*
#ifdef IZI_KATKA
#define int __int64_t
#else
#define int __int64
#endif
*/
const long long MOD = 1e9 + 7;
const long long MAXN = 1e6 + 1;
typedef long long ll;
#define pii pair<int,int>
long long readInt() {
bool minus1 = false;
long long result = 0;
char ch;
ch = getchar();
while (true) {
if (ch == '-') break;
if (ch >= '0' && ch <= '9') break;
ch = getchar();
}
if (ch == '-') minus1 = true; else result = ch-'0';
while (true) {
ch = getchar();
if (ch < '0' || ch > '9') break;
result = result*10 + (ch - '0');
}
if (minus1)
return -result;
else
return result;
}
int deg[MAXN];
int up[MAXN][22];
int cnt[MAXN];
int timer = 0;
int u[MAXN];
int v[MAXN];
int tin[MAXN];
vector<int> g[MAXN];
void dfs(int v, int par = 0) {
deg[v] = deg[par] + 1;
up[v][0] = par;
timer++;
tin[v] = timer;
for (int i = 1; i <= 20; i++) {
up[v][i] = up[up[v][i-1]][i-1];
}
for (int j : g[v]) {
if (j == par) continue;
dfs(j, v);
}
}
int lca(int a, int b) {
if (deg[a] > deg[b]) swap(a, b);
for (int i = 20; i >= 0; i--) {
if (deg[up[b][i]] >= deg[a]) {
b = up[b][i];
}
}
if (a == b) return a;
for (int i = 20; i >= 0; i--) {
if (up[b][i] != up[a][i]) {
a = up[a][i];
b = up[b][i];
}
}
return up[a][0];
}
void add(int x, int y) {
cnt[x]++;
cnt[y]++;
cnt[lca(x, y)] -= 2;
}
void dfs2(int v, int par = 0) {
for(int j : g[v]) {
if (j == par) continue;
dfs2(j, v);
cnt[v] += cnt[j];
}
}
bool cmp(const int &i, const int &j) {
return tin[i] < tin[j];
}
int main() {
#ifdef IZI_KATKA
assert(freopen("input", "r", stdin));
assert(freopen("output", "w", stdout));
#endif
int n = readInt(), m = readInt(), k = readInt();
for (int i = 1; i < n; i++) {
u[i] = readInt(), v[i] = readInt();
g[u[i]].pb(v[i]);
g[v[i]].pb(u[i]);
}
dfs(1);
for (int i = 1; i <= m; i++) {
int sz = readInt();
vector<int> tmp;
for (int j = 1; j <= sz; j++) {
tmp.pb(readInt());
}
sort(tmp.begin(), tmp.end(), cmp);
for (int j = 0; j < tmp.size(); j++) {
add(tmp[j], tmp[(j + 1) % tmp.size()]);
}
}
dfs2(1);
vector<int> ans;
for (int i = 1; i < n; i++) {
if (tin[u[i]] > tin[v[i]]) swap(u[i], v[i]);
if (cnt[v[i]] >= 2 * k) ans.pb(i);
}
cout << ans.size() << endl;
for (int i : ans) {
cout << i << ' ';
}
return 0;
}
