/*
Author: Nguyen Chi Thanh - High School for the Gifted - VNU.HCM (i2528)
*/
#include <bits/stdc++.h>
using namespace std;
/* START OF TEMPALTE */
// #define int long long
#define ll long long
#define ull unsigned long long
#define ld long double
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second
#define popcount __builtin_popcountll
#define all(x) (x).begin(), (x).end()
#define BIT(x, i) (((x) >> (i)) & 1)
#define MASK(x) (1ll << (x))
#define SZ(a) ((int32_t)a.size())
#define debug(a, l, r) {for (int _i = (l); _i <= (r); ++_i) cout << (a)[_i] << ' '; cout << '\n';}
template<class X, class Y>
bool minimize(X &x, const Y &y) {
if (x > y) {
x = y;
return true;
} else return false;
}
template<class X, class Y>
bool maximize(X &x, const Y &y) {
if (x < y) {
x = y;
return true;
} else return false;
}
/* END OF TEMPALTE */
const int MAXN = 1e5 + 5;
const int LG = 17;
int n, q, k, st[MAXN], up[LG + 1][MAXN], depth[MAXN], weight[MAXN];
vector<int> adj[MAXN];
pii edges[MAXN];
void init() {
cin >> n >> q >> k;
for (int i = 1; i < n; ++i) {
int u, v; cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
edges[i] = {u, v};
}
int timer = 0;
function<void(int, int)> dfs = [&] (int u, int par) {
st[u] = ++timer;
up[0][u] = par;
for (int j = 1; j <= LG; ++j)
up[j][u] = up[j - 1][up[j - 1][u]];
for (int v : adj[u]) {
if (v == par) continue;
depth[v] = depth[u] + 1;
dfs(v, u);
}
};
dfs(1, 0);
}
int lift(int u, int k) {
for (int j = 0; j <= LG; ++j)
if (BIT(k, j)) u = up[j][u];
return u;
}
int lca(int u, int v) {
if (depth[u] > depth[v]) swap(u, v);
v = lift(v, depth[v] - depth[u]);
if (u == v) return u;
for (int j = LG; j >= 0; --j)
if (up[j][u] != up[j][v]) {
u = up[j][u];
v = up[j][v];
}
return up[0][u];
}
void solve() {
auto incPath = [&] (int u, int v) {
int x = lca(u, v);
weight[u] += 1;
weight[v] += 1;
weight[x] -= 2;
};
for (int qr = 1; qr <= q; ++qr) {
int s; cin >> s;
vector<int> nodes;
for (int i = 1; i <= s; ++i) {
int u; cin >> u;
nodes.push_back(u);
}
sort(all(nodes), [&] (int x, int y) {
return st[x] < st[y];
});
int sz = SZ(nodes);
for (int i = 0; i < sz; ++i) {
incPath(nodes[i], nodes[(i + 1) % sz]);
}
}
function<void(int, int)> dfsWeight = [&] (int u, int par) {
for (int v : adj[u]) {
if (v == par) continue;
dfsWeight(v, u);
weight[u] += weight[v];
}
};
dfsWeight(1, 0);
vector<int> ans;
for (int i = 1; i < n; ++i) {
int target = edges[i].se;
if (depth[edges[i].fi] > depth[target])
target = edges[i].fi;
int numPath = weight[target];
// cout << edges[i].fi << ' ' << edges[i].se << '\n';
if (numPath >= 2 * k) ans.push_back(i);
}
cout << SZ(ans) << '\n';
for (auto eid : ans) cout << eid << ' ';
}
signed main() {
#ifdef NCTHANH
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
ios_base::sync_with_stdio(0);
cin.tie(nullptr); cout.tie(nullptr);
init();
solve();
return 0;
}
