#include <bits/stdc++.h>
bool M1;
#define int long long
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define REV(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
using namespace std;
#define MAXN 100005
int n, m, k;
vector<pair<int, int>> g[MAXN];
int sta[MAXN], fin[MAXN];
int dep[MAXN], up[MAXN][20];
int timer = 0;
int f[MAXN];
vector<int> ans;
///++++++++++++++++++++++++++++++++++++++///
void dfs(int u, int p) {
sta[u] = ++timer;
for (pair<int, int> &x : g[u]) {
int v, w; tie(v, w) = x;
if (v == p) continue;
dep[v] = dep[u] + 1;
up[v][0] = u;
dfs(v, u);
}
fin[u] = timer;
}
void prepare_LCA() {
FOR(j, 1, 19) FOR(i, 1, n) up[i][j] = up[up[i][j - 1]][j - 1];
}
int LCA(int a, int b) {
if (dep[a] < dep[b]) swap(a, b);
int h = dep[a] - dep[b];
for (int i = 0; (1 << i) <= h; ++i) {
if (h >> i & 1) a = up[a][i];
}
if (a == b) return a;
h = __lg(dep[a]);
for (int i = h; i >= 0; --i) {
if (up[a][i] != up[b][i]) {
a = up[a][i];
b = up[b][i];
}
}
return up[a][0];
}
void update(int a, int b) {
f[a]--;
f[b]++;
}
bool inside(int a, int b){
return (sta[a] <= sta[b] && fin[b] <= fin[a]);
}
void dp(int u, int p) {
for (pair<int, int> &x : g[u]) {
int v, id; tie(v, id) = x;
if (v == p) continue;
dp(v, u);
f[u] += f[v];
if (f[v] >= k) ans.push_back(id);
}
}
void solve() {
cin >> n >> m >> k;
FOR(i, 1, n - 1) {
int u, v; cin >> u >> v;
g[u].push_back({v, i});
g[v].push_back({u, i});
}
dfs(1, 0);
prepare_LCA();
FOR(i, 1, m) {
int numNode; cin >> numNode;
vector<int> vecNode;
FOR(j, 1, numNode) {
int curNode; cin >> curNode;
vecNode.push_back(curNode);
}
sort(vecNode.begin(), vecNode.end(), [&](const int &a, const int &b){
return sta[a] < sta[b];
});
vector<int> vecLCA;
FOR(j, 0, vecNode.size() - 2) {
vecLCA.push_back(LCA(vecNode[j], vecNode[j + 1]));
}
vecNode.insert(vecNode.end(), vecLCA.begin(), vecLCA.end());
sort(vecNode.begin(), vecNode.end(), [&](const int &a, const int &b){
return sta[a] < sta[b];
});
stack<int> st;
for (int &curNode : vecNode) {
while (st.size() && !inside(st.top(), curNode)) st.pop();
if (st.size()) update(st.top(), curNode);
st.push(curNode);
}
}
dp(1, 0);
sort(ans.begin(), ans.end());
cout << ans.size() << '\n';
for (int &x : ans) cout << x << ' ';
}
///++++++++++++++++++++++++++++++++++++++///
#define task "test"
int32_t main() {
if (fopen(task".inp","r")) {
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
ios_base::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
solve();
bool M2;
cerr << "++++++++++++++++++++++++++++\n";
cerr << "Time: " << clock() << "ms" << '\n';
cerr << "Memory: " << abs(&M2 - &M1) / 1024 / 1024 << "MB" << '\n';
cerr << "++++++++++++++++++++++++++++\n";
return 0;
}
