//IN THE NAME OF GOD
#include<bits/stdc++.h>
#pragma GCC optimize("O2,unroll-loops")
#define endl '\n'
#define F first
#define S second
#define pii pair<int,int>
#define all(x) x.begin(),x.end()
#define pb push_back
#define fast_io ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define file_io freopen("input.in" , "r" , stdin) ; freopen("output.out" , "w" , stdout);
using namespace std;
typedef long long ll;
typedef long double dll;
const int N = 1e5+7, lg = 23;
int mark[N], h[N], par[lg][N], st[N], en[N], tim, a[N];
set<int> dp[N], rem[N];
vector<pii> g[N], vec;
vector<int> ans;
void dfs(int v){
mark[v] = 1;
st[v] = ++tim;
for(int i=1; i<lg; i++) par[i][v] = par[i-1][par[i-1][v]];
for(pii cur : g[v]){
int u = cur.F;
if (mark[u]) continue;
h[u] = h[v]+1;
par[0][u] = v;
dfs(u);
}
en[v] = ++tim;
}
int lca(int v, int u){
if (h[v] < h[u]) swap(v,u);
int dif = h[v] - h[u];
for(int i=lg-1; i>=0; i--) if ((dif>>i)&1) v = par[i][v];
if (v == u) return v;
for(int i=lg-1; i>=0; i--){
if (par[i][v] != par[i][u]){
v = par[i][v];
u = par[i][u];
}
}
return par[0][v];
}
void dfs2(int v, int k){
mark[v] = 1;
for(pii cur : g[v]){
int u = cur.F, id = cur.S;
if (mark[u]) continue;
dfs2(u,k);
if (int(dp[u].size()) >= k) ans.pb(id);
if (int(dp[u].size()) > int(dp[v].size())) swap(dp[u],dp[v]);
for(int cur : dp[u]) dp[v].insert(cur);
for(int cur : rem[v]) dp[v].erase(cur);
}
}
int32_t main(){
fast_io;
int n,m,k; cin >> n >> m >> k;
for(int i=1; i<n; i++){
int v,u; cin >> v >> u;
g[v].pb({u,i});
g[u].pb({v,i});
}
dfs(1);
for(int j=1; j<=m; j++){
int x; cin >> x;
for(int i=1; i<=x; i++){
cin >> a[i];
vec.pb({st[a[i]],a[i]});
}
int lc = a[1];
for(int i=2; i<=x; i++) lc = lca(lc,a[i]);
rem[lc].insert(j);
for(int i=1; i<=x; i++) dp[a[i]].insert(j);
}
fill(mark+1,mark+n+1,0);
dfs2(1,k);
sort(all(ans));
cout << int(ans.size()) << endl;
for(int cur : ans) cout << cur << " ";
cout << endl;
return 0;
}
