#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define ll long long
#define mp(x, y) make_pair(x, y)
#define sz(v) ((int) (v).size())
#define all(v) (v).begin(), (v).end()
#define MASK(i) (1LL << (i))
#define BIT(x, y) (((x) >> (y)) & 1)
#define pb push_back
#define max_rng *max_element
#define min_rng *min_element
#define rep(i, n) for(int i = 1, _n = (n); i <= _n; ++i)
#define forn(i, a, b) for(int i = (a), _b = (b); i <= _b; ++i)
#define ford(i, a, b) for(int i = (a), _b = (b); i >= _b; --i)
template <class X, class Y>
inline bool maximize(X &x, Y y) {
return (x < y ? x = y, true : false);
}
template <class X, class Y>
inline bool minimize(X &x, Y y) {
return (x > y ? x = y, true : false);
}
template <class X>
inline void compress(vector<X> &a) {
sort(all(a));
a.resize(unique(all(a)) - a.begin());
}
int ctz(ll x) { return __builtin_ctzll(x); }
int lg(ll x) { return 63 - __builtin_clzll(x); }
int popcount(ll x) { return __builtin_popcount(x); }
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) {
return l + abs((ll) rng()) % (r - l + 1);
}
const ll oo = (ll) 1e17;
const int inf = (ll) 2e9 + 7, mod = (ll) 1e9 + 7;
const int mxn = 1e5 + 5, LOG = 20;
void add(int &x, int y) { x += y; if (x >= mod) x -= mod; }
void sub(int &x, int y) { x -= y; if (x < 0) x += mod; }
int n, m, k;
vector<pair<int, int>> g[mxn];
int timer = 0;
int in[mxn], out[mxn];
int h[mxn];
int par[mxn][LOG + 5];
int cnt[mxn], pf[mxn];
void dfs(int u, int p) {
par[u][0] = p;
h[u] = h[p] + 1;
forn(i, 1, LOG) {
par[u][i] = par[par[u][i-1]][i-1];
}
in[u] = ++timer;
for (pair<int, int> i : g[u]) if (i.first != p) {
dfs(i.first, u);
}
out[u] = timer;
}
int lift(int u, int k) {
for (; k > 0; k -= k & -k)
u = par[u][ctz(k)];
return u;
}
int lca(int u, int v) {
if (h[u] < h[v])
swap(u, v);
u = lift(u, h[u] - h[v]);
if (u == v) return u;
ford(i, lg(h[u]), 0) if (par[u][i] != par[v][i]) {
u = par[u][i];
v = par[v][i];
}
return par[u][0];
}
bool isIn(int root, int u) {
return in[root] <= in[u] && in[u] <= out[root];
}
bool compare(int &u, int &v) {
return in[u] < in[v];
}
void fix(int u = 1, int p = 0) {
for (pair<int, int> i : g[u]) if (i.first != p) {
fix(i.first, u);
pf[u] += pf[i.first];
cnt[i.second] = pf[i.first];
}
}
signed main(void) {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> n >> m >> k;
rep(i, n - 1) {
int u, v;
cin >> u >> v;
g[u].pb(mp(v, i));
g[v].pb(mp(u, i));
}
dfs(1, 0);
rep(_, m) {
int k;
cin >> k;
vector<int> req(k);
for (int &i : req) cin >> i;
sort(all(req), compare);
forn(i, 0, k - 2) req.pb(lca(req[i], req[i+1]));
compress(req);
sort(all(req), compare);
stack<int> st;
st.push(req[0]);
forn(i, 1, sz(req) - 1) {
int u = req[i];
while (!st.empty() && !isIn(st.top(), u))
st.pop();
if (!st.empty()) {
pf[st.top()]--;
pf[u]++;
}
st.push(u);
}
}
fix();
vector<int> res;
forn(i, 1, n - 1) if (cnt[i] >= k)
res.pb(i);
cout << sz(res) << '\n';
for (int v : res) cout << v << ' ';
return 0;
}
