#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
#pragma GCC optimize ("Ofast")
#define double ld
#define F first
#define S second
#define vi vector<int>
#define vvi vector<vi>
#define pi pair<int, int>
#define vpi vector<pi>
#define vb vector<bool>
#define vvb vector<vb>
#define pb push_back
#define ppb pop_back
#define read(a) for(auto &x:a) cin >> x;
#define print(a) for(auto x:a) cout << x << " "; cout << "\n";
#define rs resize
#define as assign
#define vc vector<char>
#define vvc vector<vc>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define MP make_pair
#define int long long
const int INF = 4e18;
const int inf = 2e9;
struct segTree{
int N;
vi tree;
segTree(int n){
N = (1LL<<(int)ceil(log2(n)));
tree = vi(2*N, 0);
}
void update(int k, int val){
k += N;
tree[k] += val;
for(k /= 2; k >= 1; k /= 2)
tree[k] = tree[2*k]+tree[2*k+1];
}
int query(int a, int b){
a += N, b += N;
int ans = 0;
while(a <= b){
if(a%2 == 1) ans += tree[a++];
if(b%2 == 0) ans += tree[b--];
a /= 2, b /= 2;
}
return ans;
}
};
void solve(){
int n, m, k; cin >> n >> m >> k;
vector<vpi> adj(n+1);
vvi up(n+1, vi(21));
for(int i=0; i<n-1; i++){
int u, v; cin >> u >> v;
adj[u].pb({v, i+1}); adj[v].pb({u, i+1});
}
vi in(n+1), out(n+1), d(n+1), edpar(n+1);
int time = 0;
function<void(int)> dfs = [&](int s){
in[s] = time++;
for(auto [u, ed]:adj[s])
if(u != up[s][0]){
up[u][0] = s;
d[u] = d[s]+1;
edpar[u] = ed;
dfs(u);
}
out[s] = time++;
};
dfs(1);
for(int j=1; j<=20; j++)
for(int i=1; i<=n; i++)
up[i][j] = up[up[i][j-1]][j-1];
function<int(int, int)> lca = [&](int a, int b){
if(d[a] > d[b]) swap(a, b);
for(int j=20; j>=0; j--)
if((d[b]-d[a])&(1LL<<j))
b = up[b][j];
for(int j=20; j>=0; j--)
if(up[a][j] != up[b][j])
a = up[a][j], b = up[b][j];
if(a == b) return a;
return up[a][0];
};
segTree st(2*n);
while(m--){
int sz; cin >> sz;
vi nod(sz); read(nod);
// sort(all(nod), [&](int a, int b){
// return (in[a] < in[b]);
// });
nod.pb(nod[0]);
for(int i=0; i<sz; i++){
int p = lca(nod[i], nod[i+1]);
st.update(in[p], -2);
st.update(in[nod[i]], 1);
st.update(in[nod[i+1]], 1);
}
}
vi ans;
for(int i=2; i<=n; i++)
if(st.query(in[i], out[i]) >= 2*k)
ans.pb(edpar[i]);
cout << ans.size() << "\n";
sort(all(ans));
print(ans);
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
// #ifndef ONLINE_JUDGE
// freopen("in.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
// #endif
solve();
return 0;
}
/*stolen stuff you should look for
* int overflow, array bounds
* special cases (n=1?)
* READ CONSTRAINTS
* do smth instead of nothing and stay organized
* WRITE STUFF DOWN
* DON'T GET STUCK ON ONE APPROACH
*/
