#include <bits/stdc++.h>
#define pb push_back
#define F first
#define S second
#define debug(x) cout << #x << "= " << x << ", "
#define ll long long
#define fast ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
#define SZ(x) (int) x.size()
#define wall cout << endl;
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int maxn = 1e5 + 10 , maxl = 18;
int n , m , k , par[maxl][maxn] , h[maxn] , st[maxn] , tim , val[maxn];
vector <int> adj[maxn];
vector <pair<int , int>> edges;
void dfs(int v)
{
st[v] = tim++;
for(auto u : adj[v]) if(u != par[0][v])
{
par[0][u] = v;
h[u] = h[v] + 1;
dfs(u);
}
}
bool cmp(int a , int b)
{
return st[a] < st[b];
}
int lca(int v , int u)
{
if(h[v] < h[u]) swap(v , u);
for(int i = 0 ; i < maxl ; i++) if(((h[v] - h[u]) >> i) & 1)
v = par[i][v];
if(v == u) return v;
for(int i = maxl - 1 ; i > -1 ; i--) if(par[i][v] != par[i][u])
{
v = par[i][v];
u = par[i][u];
}
return par[0][v];
}
void update(int v)
{
for(auto u : adj[v]) if(u != par[0][v])
{
update(u);
val[v] += val[u];
}
}
int32_t main()
{
fast;
cin >> n >> m >> k;
for(int i = 0 ; i < n - 1 ; i++)
{
int v , u; cin >> v >> u;
adj[v].pb(u); adj[u].pb(v);
edges.pb({u , v});
}
dfs(1);
for(int i = 1 ; i < maxl ; i++)
for(int j = 1 ; j <= n ; j++)
par[i][j] = par[i - 1][par[i - 1][j]];
while(m--)
{
vector <int> vec;
int s; cin >> s;
while(s--)
{
int x; cin >> x; vec.pb(x);
val[x]++;
}
sort(vec.begin() , vec.end() , cmp);
for(int i = 0 ; i < SZ(vec) ; i++)
{
int a = vec[i] , b = vec[(i + 1) % SZ(vec)];
int l = lca(a , b);
val[l]--;
}
}
update(1);
vector <int> ans;
for(int i = 0 ; i < n - 1 ; i++)
{
auto u = edges[i];
int a = u.F , b = u.S;
if(h[a] < h[b]) swap(a , b);
if(val[a] >= k) ans.pb(i + 1);
}
cout << SZ(ans) << endl;
for(auto u : ans) cout << u << " ";
cout << endl;
return 0;
}
