#include <bits/stdc++.h>
#define int long long int
#define ff first
#define ss second
#define FT ios_base::sync_with_stdio(false);cin.tie(0);
using namespace std;
const int maxn = 1e5 + 10;
const int mxlg = 25;
vector <int> adj[maxn];
int st[maxn] , cnt , f[maxn] , p[maxn][mxlg] , h[maxn];
pair <int , int> edge[maxn];
vector <int> ans;
///////////////////////////////////////////////////////
void dfs (int v , int g)
{
st[v] = ++cnt;
p[v][0] = g;
h[v] = h[g] + 1;
for (int i = 1 ; i < mxlg ; i++)
{
int x = p[v][i - 1];
p[v][i] = p[x][i - 1];
}
for (auto u : adj[v])
{
if (u != g)
{
dfs(u , v);
f[v] += f[u];
}
}
}
//////////////////////////////////////////////////////////
int lca (int a , int b)
{
if (h[b] > h[a])
{
swap (a , b);
}
for (int i = mxlg - 1 ; i >= 0 ; i--)
{
if (h[p[a][i]] >= h[b])
{
a = p[a][i];
}
}
if (a == b)
{
return a;
}
for (int i = mxlg - 1 ; i >= 0 ; i--)
{
if (p[a][i] != p[b][i])
{
a = p[a][i];
b = p[b][i];
}
}
return p[a][0];
}
//////////////////////////////////////////////////////////////
signed main() {
FT;
int n , m , k;
cin >> n >> m >> k;
for (int i = 1 ; i < n ; i++)
{
int a , b;
cin >> a >> b;
adj[a].push_back(b);
adj[b].push_back(a);
edge[i] = {a , b};
}
dfs (1 , 0);
for (int i = 1 ; i <= m ; i++)
{
vector <pair <int , int>> S;
int sz;
cin >> sz;
for (int j = 1 ; j <= sz ; j++)
{
int x;
cin >> x;
S.push_back({st[x] , x});
}
sort (S.begin() , S.end());
for (int j = 0 ; j < sz - 1 ; j++)
{
f[S[j].ss]++;
f[S[j + 1].ss]++;
f[lca (S[j].ss , S[j + 1].ss)] -= 2;
}
f[S[0].ss]++;
f[S[sz - 1].ss]++;
f[lca (S[0].ss , S[sz - 1].ss)] -= 2;
}
dfs (1 , 0);
for (int i = 1 ; i < n ; i++)
{
int u = edge[i].ff , v = edge[i].ss;
if (h[v] < h[u])
{
swap (u , v);
}
if (f[v] >= 2 * k)
{
ans.push_back(i);
}
}
cout << ans.size() << endl;
for (auto i : ans)
{
cout << i << " ";
}
return 0;
}
