#pragma GCC optimize("-O3")
#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define vl vector<ll>
#define vi vector<int>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define pb push_back
#define p_b pop_back
#define f first
#define s second
using namespace std;
using namespace __gnu_pbds;
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
const ll sz = 1e5+5;
vl g[sz];
ll vis[sz], lev[sz], intime[sz], p[30][sz], dist[sz], tin = 1;
void dfs(ll node)
{
vis[node] = 1;
intime[node] = tin++;
for(auto u : g[node])
{
if(vis[u])
continue;
lev[u] = lev[node] + 1;
p[0][u] = node;
dfs(u);
}
}
ll jump(ll x, ll k)
{
for(ll i = 0; i < 27; i++)
{
if((k >> i) & 1)
x = p[i][x];
}
return x;
}
ll lca(ll x, ll y)
{
if(lev[x] > lev[y])
swap(x, y);
ll d = lev[y] - lev[x];
y = jump(y, d);
if(x == y)
return x;
else
{
for(ll i = 26; i >= 0; i--)
{
if(p[i][x] != p[i][y])
{
x = p[i][x];
y = p[i][y];
}
}
return p[0][x];
}
}
void dfs2(ll node)
{
vis[node] = 1;
for(auto u : g[node])
{
if(vis[u])
continue;
dfs2(u);
dist[node] += dist[u];
}
}
void solve()
{
ll n, m, k, i, j;
cin >> n >> m >> k;
vector<pll>edges;
for(i = 1; i <= n - 1; i++)
{
ll x, y;
cin >> x >> y;
edges.pb({x, y});
g[x].pb(y);
g[y].pb(x);
}
dfs(1);
for(i = 1; i < 27; i++)
{
for(j = 1; j <= n; j++)
p[i][j] = p[i-1][p[i-1][j]];
}
for(i = 1; i <= m; i++)
{
ll s;
cin >> s;
vector<pll>vect;
for(j = 1; j <= s; j++)
{
ll x;
cin >> x;
vect.pb({intime[x], x});
}
sort(all(vect));
vect.pb({vect[0].f, vect[0].s});
for(j = 0; j < s; j++)
{
ll x = vect[j].s, y = vect[j+1].s;
ll a = lca(x, y);
dist[x]++;
dist[y]++;
dist[a] -= 2;
}
}
for(i = 1; i <= n; i++)
vis[i] = 0;
dfs2(1);
vl f;
for(i = 0; i < edges.size(); i++)
{
ll x = edges[i].f, y = edges[i].s;
if(p[0][x] != y)
swap(x, y);
if(dist[x] >= 2 * k)
f.pb(i+1);
}
cout << f.size() << "\n";
for(auto u : f)
cout << u << ' ';
cout << "\n";
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
ll tests = 1;
//cin >> tests;
while(tests--)
{
solve();
}
}
