#include <bits/stdc++.h>
#define fast ios_base::sync_with_stdio(0);cin.tie(NULL);cout.tie(NULL)
#define ll long long
#define F first
#define S second
using namespace std;
const int N = 100005, MOD = 1e9 + 7;
vector<ll> graph[N];
ll pre[N], dp[N][(ll) log2(100005)], n, m, s, lvl[N], tin[N], tout[N], timer = 0, u[N], v[N], fenwick[N];
void dfs(int source, int par, int level){
dp[source][0] = par;
lvl[source] = level;
tin[source] = ++timer;
for(auto k : graph[source])
if(k != par)
dfs(k, source, level + 1);
tout[source] = timer;
}
void init(){
dfs(1, -1, 0);
for(int i = 1; i <= (log2(n)); ++i)
for(int j = 1; j <= n; ++j)
if(dp[j][i - 1] != -1)
dp[j][i] = dp[dp[j][i - 1]][i - 1];
}
ll LCA(int u, int v){
if(lvl[u] > lvl[v]) swap(u, v);
ll d = lvl[v] - lvl[u];
while(d){
int jump = log2(d);
v = dp[v][jump];
d -= pow(2, jump);
}
if(v == u)
return v;
for(int i = log2(n); i >= 0; --i){
if(dp[v][i] != -1 && dp[v][i] != dp[u][i]){
u = dp[u][i];
v = dp[v][i];
}
}
return dp[v][0];
}
int get(int node){
int ans = 0;
for(int i = node; i >= 1; i -= (i & -i))
ans += fenwick[i];
return ans;
}
void upd(int node, int val){
for(int i = node; i <= n; i += (i & -i))
fenwick[i] += val;
}
bool cmp(int x, int y){
return tin[x] < tin[y];
}
void edges(int node, int par){
for(auto k : graph[node]){
if(k == par) continue;
edges(k, node);
pre[node] += pre[k];
}
}
void solve(){
cin >> n >> m >> s;
for(int i = 1; i <= n - 1; ++i){
cin >> u[i] >> v[i];
graph[u[i]].push_back(v[i]);
graph[v[i]].push_back(u[i]);
}
memset(dp, -1, sizeof dp);
init();
while(m--){
int r;
cin >> r;
vector<int> a;
for(int i = 0; i < r; ++i){
int x;
cin >> x;
a.push_back(x);
}
sort(a.begin(), a.end(), cmp);
a.push_back(a[0]);
for(int i = 0; i < r; ++i){
int p = LCA(a[i], a[i + 1]);
pre[a[i]]++;
pre[a[i + 1]]++;
pre[p] -= 2;
}
}
edges(1, 0);
vector<int> ans;
for(int i = 1; i <= n - 1; ++i){
if(lvl[u[i]] > lvl[v[i]])
swap(u[i], v[i]);
int x = pre[v[i]];
if(x >= 2*s)
ans.push_back(i);
}
cout << ans.size() << '\n';
for(auto k : ans) cout << k << ' ';
}
int main() {
fast;
int t = 1;
// cin >> t;
while(t--)
solve();
return 0;
}
