#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
#define fastio ios::sync_with_stdio(false), cin.tie(0)
#define pb push_back
#define eb emplace_back
#define f first
#define s second
#define int long long
const int maxn = 2e5 + 5;
int n, m, k;
int succ[maxn][18], dep[maxn];
int sz[maxn], head[maxn], in[maxn], dfn = 0;
vector<pll> adj[maxn];
vector<int> ans;
void dfs(int pos, int prev){
sz[pos] = 1;
succ[pos][0] = prev;
for(int i = 1; i < 18; i++) succ[pos][i] = succ[succ[pos][i - 1]][i - 1];
for(auto &k : adj[pos]){
int x, id;
tie(x, id) = k;
if(x == prev) continue;
adj[x].erase(find(adj[x].begin(), adj[x].end(), pll(pos, id)));
dep[x] = dep[pos] + 1;
dfs(x, pos);
sz[pos] += sz[x];
if(sz[x] > sz[adj[pos][0].f]) swap(k, adj[pos][0]);
}
}
void decompose(int pos, int h){
head[pos] = h;
in[pos] = ++dfn;
for(auto [x, id] : adj[pos]){
if(pll(x, id) == adj[pos][0]) decompose(x, h);
else decompose(x, x);
}
}
int lift(int b, int s){
for(int i = 17; i >= 0; i--){
if(s & (1 << i)) b = succ[b][i];
}
return b;
}
int find_lca(int a, int b){
if(dep[a] > dep[b]) swap(a, b);
b = lift(b, dep[b] - dep[a]);
if(a == b) return a;
for(int i = 17; i >= 0; i--){
if(succ[a][i] != succ[b][i]) a = succ[a][i], b = succ[b][i];
}
return succ[a][0];
}
int st[maxn * 4];
void push(int v){
st[v * 2] += st[v], st[v * 2 + 1] += st[v], st[v] = 0;
}
void upd(int l, int r, int val, int v = 1, int L = 0, int R = n){
if(l > R || r < L) return;
if(l <= L && r >= R){
st[v] += val;
return;
}
push(v);
int m = (L + R) / 2;
upd(l, r, val, v * 2, L, m);
upd(l, r, val, v * 2 + 1, m + 1, R);
}
int qry(int pos, int v = 1, int l = 0, int r = n){
if(l == r) return st[v];
push(v);
int m = (l + r) / 2;
if(pos <= m) return qry(pos, v * 2, l, m);
else return qry(pos, v * 2 + 1, m + 1, r);
}
void path_aggregate(int a, int b, int val){
// dep[a] < dep[b], lca(a, b) = a
while(head[b] != head[a]){
upd(in[head[b]], in[b], val);
b = succ[head[b]][0];
}
upd(in[a], in[b], val);
}
void dfs2(int pos, int id = -1){
if(id != -1){
if(qry(in[pos]) >= k) ans.pb(id);
}
for(auto [x, id] : adj[pos]){
dfs2(x, id);
}
}
signed main(void){
// fastio;
cin>>n>>m>>k;
for(int i = 0; i < n - 1; i++){
int a, b;
cin>>a>>b;
a--, b--;
adj[a].eb(b, i), adj[b].eb(a, i);
}
dfs(0, 0);
decompose(0, 0);
for(int i = 0; i < m; i++){
int d;
cin>>d;
vector<int> a(d);
for(int j = 0; j < d; j++) cin>>a[j], a[j] --;
sort(a.begin(), a.end(), [&](int x, int y){ return in[x] < in[y];});
a.erase(unique(a.begin(), a.end()), a.end());
if(d < 2) continue;
int glca = find_lca(a[0], a[1]);
for(int j = 2; j < d; j++) glca = find_lca(glca, a[j]);
int prev = glca;
for(int j = 0; j < d; j++){
int lca = find_lca(prev, a[j]);
path_aggregate(glca, a[j], 1);
path_aggregate(glca, lca, -1);
prev = a[j];
}
}
dfs2(0, -1);
sort(ans.begin(), ans.end());
cout<<ans.size()<<"\n";
for(auto x : ans) cout<<x + 1<<" ";
cout<<"\n";
}
