#include<bits/stdc++.h>
using namespace std;
using int64 = int64_t;
#define REP(i, n) for(int i = 0, _n = n; i < _n; ++i)
#define REPD(i, n) for(int i = n - 1; i >= 0; --i)
#define FOR(i, l, r) for(int i = l, _r = r; i <= _r; ++i)
#define FORD(i, r, l) for(int i = r, _l = l; i >= _l; --i)
#define left __left
#define right __right
#define prev __prev
#define next __next
#define div __div
#define pb push_back
#define pf push_front
#define sz(v) (int)v.size()
#define range(v) begin(v), end(v)
#define compact(v) v.erase(unique(range(v)), end(v))
#define debug(v) "[" #v " = " << (v) << "]"
template<typename T>
bool minimize(T& a, const T& b){
if(a > b){
a = b;
return true;
}
return false;
}
template<typename T>
bool maximize(T& a, const T& b){
if(a < b){
a = b;
return true;
}
return false;
}
template<int dimension, class T>
struct vec : public vector<vec<dimension - 1, T>> {
static_assert(dimension > 0, "Dimension must be positive !\n");
template<typename... Args>
vec(int n = 0, Args... args) : vector<vec<dimension - 1, T>>(n, vec<dimension - 1, T>(args...)) {}
};
template<class T>
struct vec<1, T> : public vector<T> {
vec(int n = 0, T val = T()) : vector<T>(n, val) {}
};
void init(void);
void process(void);
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
#define task "antuvu"
if(fopen(task".inp", "r")){
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
int T = 1; //cin >> T;
while(T--) {
init();
process();
}
return 0;
}
const int MAX = 1e5 + 5;
int n, m, k, timer_dfs;
int tour[MAX], cnt[MAX], eu[MAX], ev[MAX], depth[MAX], par[MAX], head[MAX], pos[MAX], heavy[MAX], count_children[MAX], diff[MAX], edge_indices[MAX];
vector<int> adj[MAX];
void init(){
cin >> n >> m >> k;
REP(i, n - 1){
int u, v;
cin >> u >> v;
adj[u].pb(i);
adj[v].pb(i);
eu[i] = u, ev[i] = v;
}
}
void pre_dfs(int u, int pre){
count_children[u] = 1;
for(int id : adj[u]) if(id != pre){
int v = eu[id] ^ ev[id] ^ u;
depth[v] = depth[u] + 1;
par[v] = u;
edge_indices[v] = id;
pre_dfs(v, id);
count_children[u] += count_children[v];
if(count_children[heavy[u]] < count_children[v]){
heavy[u] = v;
}
}
}
void decompose(int u, int c){
head[u] = c;
tour[pos[u] = ++timer_dfs] = u;
if(heavy[u]){
decompose(heavy[u], c);
for(int id : adj[u]){
int v = eu[id] ^ ev[id] ^ u;
if(par[v] == u and v != heavy[u]){
decompose(v, v);
}
}
}
}
int getLCA(int u, int v){
while(head[u] != head[v]){
if(depth[head[u]] < depth[head[v]]){
v = par[head[v]];
}
else{
u = par[head[u]];
}
}
if(depth[u] < depth[v]) return u;
else return v;
}
void add_range_sum(int l, int r, int v){
diff[l] += v;
diff[r + 1] -= v;
}
void add_sum(int u, int v){
while(head[u] != head[v]){
if(depth[head[u]] < depth[head[v]]) swap(u, v);
add_range_sum(pos[head[u]], pos[u], 1);
u = par[head[u]];
}
if(u != v){
if(depth[u] > depth[v]) swap(u, v);
add_range_sum(pos[u] + 1, pos[v], 1);
}
}
bool is_parent(int u, int v){
return pos[u] <= pos[v] and pos[v] <= pos[u] + count_children[u] - 1;
}
void solve_difference(){
FOR(i, 2, n){
diff[i] += diff[i - 1];
cnt[edge_indices[tour[i]]] = diff[i];
}
}
void process(){
pre_dfs(1, -1);
decompose(1, 1);
while(m--){
int s;
cin >> s;
vector<int> ar(s);
REP(i, s) cin >> ar[i];
sort(range(ar), [&](int a, int b){
return pos[a] < pos[b];
});
REP(i, s - 1){
ar.pb(getLCA(ar[i], ar[i + 1]));
}
sort(range(ar), [&](int a, int b){
return pos[a] < pos[b];
});
compact(ar);
stack<int> stack_vertices;
stack_vertices.push(ar[0]);
FOR(i, 1, sz(ar) - 1){
while(!stack_vertices.empty() and !is_parent(stack_vertices.top(), ar[i])){
stack_vertices.pop();
}
add_sum(stack_vertices.top(), ar[i]);
stack_vertices.push(ar[i]);
}
}
solve_difference();
vector<int> res;
REP(i, n - 1){
if(cnt[i] >= k){
res.pb(i);
}
}
cout << sz(res) << '\n';
for(int i : res) cout << i + 1 << ' ';
}
