#include<bits/stdc++.h>
using namespace std;
#define int long long
#define f first
#define s second
const int N = 1e5 + 69;
const int lg = 17;
int up[N][lg];
int n, m, k, tin[N], tout[N], timer;
vector<int> g[N];
set<int> st[N], er[N];
set<tuple<int, int, int>> edges;
vector<int> ans;
bool anc(int v, int u) {
return tin[v] <= tin[u] && tout[v] >= tout[u];
}
int lca(int a, int b) {
if (anc(a, b))
return a;
else if (anc(b, a))
return b;
for (int i = lg - 1;i >= 0;i--) {
if (!anc(up[a][i], b) && up[a][i] > 0)
a = up[a][i];
}
return up[a][0];
}
void dfs(int v, int p) {
tin[v] = ++timer;
up[v][0] = p;
for (int i = 1;i < lg;i++)
up[v][i] = up[up[v][i - 1]][i - 1];
for (auto u : g[v]) {
if (u == p)
continue;
dfs(u, v);
}
tout[v] = timer;
}
void solve(int v, int p) {
for (auto u : g[v]) {
if (u == p)
continue;
solve(u, v);
if (st[v].size() < st[u].size())
swap(st[u], st[v]);
for (auto x : st[u])
st[v].insert(x);
}
for (auto u : er[v]) {
assert(st[v].count(u) > 0);
st[v].erase(u);
}
if (p != 0) {
int a = v, b = p;
if (a > b)
swap(a, b);
if (st[v].size() == k) {
auto u = *edges.lower_bound({a, b, -1});
ans.push_back(get<2>(u));
}
}
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int tt = 1;
//cin >> tt;
while (tt--) {
cin >> n >> m >> k;
for (int i = 1;i <= n - 1;i++) {
int a, b;
cin >> a >> b;
g[a].push_back(b);
g[b].push_back(a);
if (a > b)
swap(a, b);
edges.insert({a, b, i});
}
dfs(1, 0);
for (int i = 1;i <= m;i++) {
int s;
cin >> s;
vector<int> y(s);
for (int j = 0;j < s;j++)
cin >> y[j];
int lc = y[0];
for (int j = 1; j < s;j++)
lc = lca(lc, y[j]);
er[lc].insert(i);
for (int j = 0;j < s;j++) {
if (y[j] != lc)
st[y[j]].insert(i);
}
}
solve(1, 0);
sort(ans.begin(), ans.end());
cout << ans.size() << '\n';
for (auto u : ans)
cout << u << " ";
}
return 0;
}
