#pragma GCC optimization O2
#pragma GCC optimization "unroll-loop"
#pragma target ("avx2")
#include <bits/stdc++.h>
#define ll int
#define ld long double
#define fs first
#define sc second
using namespace std;
typedef pair<ll,ll> LL;
const ll N = 1e5 + 9;
const ll Log2 = 21;
const ll inf = 1e9 + 7;
vector<ll> g[N];
ll n,Q,k,x,y,par[N][Log2],pos[N],child[N],nTime,d[N];
ll tot[N];
void DFS(ll u,ll p){
child[u] = 1; pos[u] = nTime++;
for (ll i = 1;i < Log2;i++) if ((1 << i) <= d[u])
par[u][i] = par[par[u][i - 1]][i - 1];
for (auto i : g[u]){
if (i == p) continue;
d[i] = d[u] + 1; par[i][0] = u;
DFS(i,u); child[u] += child[i];
}
}
ll LCA(ll u,ll v){
if (d[u] > d[v]) swap(u,v);
for (ll i = Log2 - 1;i >= 0;i--) if ((1 << i) <= d[v] && d[par[v][i]] >= d[u])
v = par[v][i];
if (u == v) return u;
for (ll i = Log2 - 1;i >= 0;i--) if (par[u][i] != par[v][i])
u = par[u][i],v = par[v][i];
return par[u][0];
}
void reDFS(ll u,ll p){
//cout<<u<<" "<<p<<"\n";
for (auto i : g[u]) if (i != p){
reDFS(i,u); tot[u] += tot[i];
}
}
bool lf(ll x,ll y){
return pos[x] < pos[y];
}
vector<LL> edge;
int main(){
ios_base::sync_with_stdio(NULL); cin.tie(0); cout.tie(0);
#define task "test"
if (fopen(task".INP","r")){
freopen(task".INP","r",stdin);
//freopen(task".OUT","w",stdout);
}
cin>>n>>Q>>k;
for (ll i = 1;i < n;i++){
cin>>x>>y; edge.push_back({x,y});
g[x].push_back(y); g[y].push_back(x);
}
DFS(1,0);
while(Q--){
vector<ll> v; ll sz,x;
cin>>sz;
for (ll i = 1;i <= sz;i++) cin>>x,v.push_back(x),tot[x]++;
sort(v.begin(),v.end(),lf); tot[LCA(v[0],v.back())]--;
for (ll i = 1;i < v.size();i++){
ll cur = LCA(v[i],v[i - 1]); tot[cur]--;
}
}
vector<ll> ans; reDFS(1,0);
//for (ll i = 1;i <= n;i++) cout<<tot[i]<<" "; return 0;
for (ll i = 0;i < n - 1;i++){
ll x = edge[i].fs,y = edge[i].sc;
if (pos[x] < pos[y]) swap(x,y);
if (tot[x] >= k) ans.push_back(i + 1);
}
cout<<ans.size()<<"\n";
for (auto i : ans) cout<<i<<" ";
}
