#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define el cout << '\n'
#define f1(i,n) for(int i=1;i<=n;i++)
#define __file_name ""
using namespace std;
const ll maxn = 1e5+5, inf=1e18;
struct FenwickTree{
int n;
vector<long long> bit;
FenwickTree(){}
FenwickTree(int n): n(n), bit(n+1, 0LL){}
void update(int idx, long long v){
if(idx <= 0) return;
for(;idx<=n;idx+=(idx&-idx)) bit[idx]+=v;
}
long long getSum(int idx){
if(idx <= 0) return 0;
long long res = 0;
for(;idx;idx-=idx&-idx) res += bit[idx];
return res;
}
};
int n,m,k,id[maxn];
vector<int> G[maxn], all, st, ans;
FenwickTree bit;
map<pair<int,int>, int> mp;
int sp[maxn], ep[maxn], timer = 1;
void tour(int u, int p){
sp[u] = timer++;
for(int c: G[u]){
if(c != p) tour(c, u);
}
ep[u] = timer - 1;
}
int par[17][maxn], depth[maxn];
void binlift(int u, int p){
par[0][u] = p;
f1(i, 16) par[i][u] = par[i-1][par[i-1][u]];
for(int c: G[u]){
if(c != p) {
id[c] = mp[{c, u}];
depth[c] = depth[u] + 1;
binlift(c, u);
}
}
}
int jump(int u, int l){
for(int i=0;i<17;i++){
if(l & (1 << i)) u = par[i][u];
}
return u;
}
int LCA(int u, int v){
if(depth[u] > depth[v]) swap(u, v);
v = jump(v, depth[v] - depth[u]);
if(u == v) return u;
for(int i=16;i>=0;i--){
if(par[i][u] != par[i][v]){
u = par[i][u];
v = par[i][v];
}
}
return par[0][u];
}
bool cmp(int u, int v){
return sp[u] < sp[v];
}
bool isParent(int u, int v){
return sp[u] <= sp[v] && ep[v] <= ep[u];
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
if(fopen(__file_name ".inp", "r")){
freopen(__file_name ".inp","r",stdin);
freopen(__file_name ".out","w",stdout);
}
// code here
cin >> n >> m >> k;
f1(i,n-1){
ll u, v; cin >> u >> v;
G[u].push_back(v);
G[v].push_back(u);
mp[{u, v}] = i;
mp[{v, u}] = i;
}
bit = FenwickTree(n);
tour(1, 0);
binlift(1, 0);
while(m--){
int s; cin >> s;
all.clear();
f1(i, s){
int u; cin >> u;
all.push_back(u);
}
sort(all.begin(), all.end(), cmp);
for(int i=1;i<s;i++){
all.push_back(LCA(all[i], all[i-1]));
}
sort(all.begin(), all.end(), cmp);
all.resize(unique(all.begin(), all.end()) - all.begin());
st.clear();
st.push_back(all.front());
for(int i=1;i<all.size();i++){
while(!isParent(st.back(), all[i])){
st.pop_back();
}
bit.update(sp[st.back()], -1);
bit.update(sp[all[i]], 1);
st.push_back(all[i]);
}
}
f1(i,n){
if(bit.getSum(ep[i]) - bit.getSum(sp[i] - 1) >= k){
ans.push_back(id[i]);
}
}
sort(ans.begin(), ans.end());
cout << ans.size();el;
for(int item: ans) cout << item << ' ';
return 0;
}
