#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define stdI freopen("input.txt", "r", stdin);
#define stdO freopen("output.txt", "w", stdout);
#define all(x) x.begin(), x.end()
#define mp(x, y) make_pair(x, y)
#define int long long
#define F first
#define S second
using namespace std;
using namespace __gnu_pbds;
typedef tree<int,
null_type,less<int>,
rb_tree_tag,
tree_order_statistics_node_update> ordered_set;
typedef pair<int, int> pii;
const int MAXN = 2e5 + 100, MAXLOG = 20, INF = 1e18, MOD = 1e9 + 7;
struct ad
{
int u, i;
};
vector<ad> adj[MAXN];
vector<int> ans;
int st[MAXN], h[MAXN], par[MAXN][MAXLOG], cnt[MAXN];
int n, m, k, t;
bool cmp(int a, int b)
{
return st[a] < st[b];
}
void predfs(int v, int p)
{
par[v][0] = p;
st[v] = ++t;
for(int i = 1; i < MAXLOG; i++)
{
par[v][i] = par[par[v][i - 1]][i - 1];
}
for(auto u : adj[v])
{
if(u.u != p)
{
h[u.u] = h[v] + 1;
predfs(u.u, v);
}
}
t++;
}
int lca(int u, int v)
{
if(h[u] < h[v])
{
swap(u, v);
}
for(int i = MAXLOG - 1; i > -1; i--)
{
if(h[par[u][i]] >= h[v])
{
u = par[u][i];
}
}
if(u == v)
{
return v;
}
for(int i = MAXLOG - 1; i > -1; i--)
{
if(par[u][i] != par[v][i])
{
u = par[u][i]; v = par[v][i];
}
}
return par[u][0];
}
void dfs(int v, int p, int ip)
{
for(auto u : adj[v])
{
if(u.u != p)
{
dfs(u.u, v, u.i);
cnt[v] += cnt[u.u];
}
}
if(cnt[v] >= 2 * k && v != 1)
{
ans.push_back(ip);
}
}
void solve()
{
cin >> n >> m >> k; h[0] = -INF;
for(int i = 1; i < n; i++)
{
int u, v; cin >> u >> v;
adj[u].push_back({v, i}); adj[v].push_back({u, i});
}
predfs(1, 0);
for(int i = 0; i < m; i++)
{
int w; cin >> w;
int t[w];
for(int j = 0; j < w; j++)
{
cin >> t[j];
}
sort(t, t + w, cmp);
for(int j = 1; j < w; j++)
{
cnt[t[j]]++; cnt[t[j - 1]]++;
cnt[lca(t[j], t[j - 1])] -= 2;
}
cnt[t[0]]++; cnt[t[w - 1]]++;
cnt[lca(t[0], t[w - 1])] -= 2;
}
dfs(1, 0, 0);
cout << ans.size() << "\n";
for(auto x : ans)
{
cout << x << " ";
}
cout << "\n";
}
int32_t main()
{
IOS;
int t = 1;
//cin >> t;
while(t--)
{
solve();
}
return 0;
}
