#include <bits/stdc++.h>
using namespace std;
const int MAXN = 100005;
#define bitinc(x) x&-x
int n, m, k;
vector<int> adj[MAXN];
int par[100005][20];
int tmp = 0, in[200005], ot[200005], bit[200005];
int sum(int ind)
{
int sm = 0;
while(ind > 0)
{
sm += bit[ind];
ind -= bitinc(ind);
}
return sm;
}
void upd(int ind, int val)
{
while(ind <= n)
{
bit[ind] += val;
ind += bitinc(ind);
}
}
vector<pair<int, int> > eg;
void dfs(int v, int p)
{
in[v] = ++tmp;
par[v][0] = p;
for(int i = 1; i < 20; i++)
par[v][i] = par[par[v][i-1]][i-1];
for(int x : adj[v])
{
if(x == p) continue;
dfs(x,v);
}
ot[v] = ++tmp;
}
bool anc(int u, int v)
{
return (in[u] <= in[v] && ot[u] >= ot[v]);
}
// method finding all lca's
int lca(int u, int v)
{
if(anc(u,v))
return u;
for(int i = 19; i >= 0; i--)
{
// as a verifier make sure par[u][i] >= 0 s.t. no array out of bounds
if(par[u][i] >= 0 && !anc(par[u][i], v))
u = par[u][i];
}
return par[u][0];
}
bool comp(int a, int b)
{
return in[a] < in[b];
}
int main()
{
cin >> n >> m >> k;
for(int i = 1; i < n; i++)
{
int u, v; cin >> u >> v;
--u; --v;
adj[u].push_back(v);
adj[v].push_back(u);
eg.push_back({u,v});
}
dfs(0, 0);
for(int i = 0; i < m; i++)
{
int s; cin >> s;
vector<int> v;
for(int i = 0; i < s; i++)
{
int w; cin >> w;
--w;
v.push_back(w);
}
sort(v.begin(), v.end(), comp);
for(int i = 0; i < s; i++)
{
int a = v[i];
int b = v[(i+1)%s];
int c = lca(v[i], v[(i+1)%s]);
upd(in[a], 1);
upd(in[b], 1);
upd(in[c], -2);
}
}
vector<int> ans;
for(int i = 0; i < n-1; i++)
{
pair<int, int> p = eg[i];
if(in[p.first] > in[p.second]) swap(p.first, p.second);
int ret = sum(ot[p.second]) - sum(in[p.second]-1);
if(ret >= 2*k) ans.push_back(i+1);
}
cout << ans.size() << endl;
for(int x : ans) cout << x << " ";
cout << endl;
}
