#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define pii pair <int , int>
#define arr3 array <int , 3>
using namespace std;
const int INF = 1e18 + 7;
const int maxn = 1e5 + 7;
int n , m , k , jump[maxn][20] , depth[maxn];
map <pii , int> ind;
vector <int> g[maxn];
vector <int> del[maxn];
vector <int> add[maxn];
vector <int> ans;
void dfsbuild(int u , int p)
{
for(int v: g[u])
{
if(v == p) continue;
jump[v][0] = u;
depth[v] = depth[u] + 1;
dfsbuild(v , u);
}
}
void build()
{
dfsbuild(1 , 1);
for(int j = 1; j < 20; j++)
{
for(int i = 1; i <= n; i++)
{
jump[i][j] = jump[jump[i][j-1]][j-1];
}
}
}
int LCA(int u , int v)
{
if(depth[u] > depth[v]) swap(u , v);
for(int i = 17; i >= 0; i--)
{
if(depth[jump[v][i]] >= depth[u])
{
v = jump[v][i];
}
}
if(u == v) return u;
for(int i = 17; i >= 0; i--)
{
if(jump[v][i] != jump[u][i])
{
u = jump[u][i];
v = jump[v][i];
}
}
return jump[u][0];
}
void merging(set<int> &a, set<int> &b)
{
if (a.size() < b.size()) swap(a, b);
a.insert(b.begin(), b.end());
}
set <int> dfs(int u , int p)
{
set <int> res;
for(int id: add[u]) res.insert(id);
for(int v: g[u])
{
if(v == p) continue;
set <int> cc = dfs(v , u);
merging(res , cc);
}
for(int id: del[u]) res.erase(id);
if(res.size() >= k)
{
ans.push_back(ind[{u , jump[u][0]}]);
}
return res;
}
void solve()
{
cin >> n >> m >> k;
for(int i = 1; i < n; i++)
{
int u , v; cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
ind[{u , v}] = i;
ind[{v , u}] = i;
}
build();
while(m--)
{
int s; cin >> s;
vector <int> a(s);
for(int i = 0; i < s; i++) cin >> a[i];
int lca = a[0];
for(int i = 1; i < s; i++) lca = LCA(lca , a[i]);
del[lca].push_back(m);
for(int i = 0; i < s; i++) {add[a[i]].push_back(m);}
}
dfs(1 , 1);
cout << (int)ans.size() << '\n';
sort(ans.begin() , ans.end());
for(int id: ans) cout << id << ' ';
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
solve();
return 0;
}
