#include<bits/stdc++.h>
using namespace std;
#define int long long
#define in pair<int, int>
#define f first
#define s second
#define pb push_back
#define pob pop_back
#define INF (int)1e17
#define MX (int)3e5+5
#define LOGM (int)18
#define fast() ios_base::sync_with_stdio(false); cin.tie(NULL)
vector<int> adj[MX];
vector<in> edges;
int pa[LOGM][MX];
int tin[MX];
int tout[MX];
int focus[MX];
int timer = 0;
int label[MX];
void dfs(int u, int p)
{
pa[0][u] = p;
tin[u] = ++timer;
for(int v: adj[u])
{
if(v==p)
continue;
dfs(v, u);
}
tout[u] = timer;
return;
}
int lca(int u, int v)
{
if(tin[u] > tin[v])
swap(u, v);
if((tout[u] >= tout[v]))
return u;
for(int i = LOGM-1; i >= 0; i--)
{
if(tout[pa[i][u]] < tout[v])
u = pa[i][u];
}
return pa[0][u];
}
void dfs2(int u, int p)
{
for(int v: adj[u])
{
if(v==p)
continue;
dfs2(v, u);
focus[u]+=focus[v];
}
return;
}
signed main()
{
fast();
int n, q, k;
cin >> n >> q >> k;
int m = n-1;
while(m--)
{
int u, v;
cin >> u >> v;
adj[u].pb(v);
adj[v].pb(u);
edges.pb({u, v});
}
dfs(1, 0);
int curr = 0;
for(auto [x, y]: edges)
{
if(tin[x] >= tin[y])
swap(x, y);
label[y] = ++curr;
}
pa[0][0] = 0;
tout[0] = INF;
for(int i = 1; i < LOGM; i++)
{
for(int j = 0; j <= n; j++)
pa[i][j] = pa[i-1][pa[i-1][j]];
}
while(q--)
{
int M;
cin >> M;
vector<in> v;
for(int QoIGn = 1; QoIGn <= M; QoIGn++)
{
int u;
cin >> u;
v.pb({tin[u], u});
}
sort(v.begin(), v.end());
for(int i = 0; i < v.size(); i++)
{
focus[lca(v[i].s, v[(i+1)%M].s)]--;
focus[v[i].s]++;
}
}
/*cout << "printign tin[u], tout[u]" << endl;
for(int u = 1; u <= n; u++)
{
printf("tin[%d] = %d, tout[%d] = %d", u, tin[u], u, tout[u]);
cout << endl;
}
cout << "printing lcas NIGELTS" << endl;
for(int i = 2; i <= n; i++)
{
for(int j = i+1; j <= n; j++)
{
printf("lca(%d, %d) = %d", i, j, lca(i, j));
cout << endl;
}
}*/
dfs2(1, 0);
int cnt = 0;
vector<int> DOFINQ;
for(int i = 1; i <= n; i++)
{
if(focus[i] >= k)
DOFINQ.pb(label[i]);
}
cout << DOFINQ.size() << "\n";
for(int ttt: DOFINQ)
cout << ttt << " ";
return 0;
}
