#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pll pair<ll, ll>
#define fi first
#define se second
#define pb push_back
const int N = 1e5+5;
const long long mod = 1e9+7;
const int base = 300;
ll m, n, k, a[N], ans, b[N], tong, d[N], c[N], lab[N], cnt, t, dp[N], h[N], P[N][20];
vector<pll> val[N];
vector<ll> adj[N], res;
ll pw(ll k, ll n)
{
ll total = 1;
for(; n; n >>= 1)
{
if(n & 1)total = total * k % mod;
k = k * k % mod;
}
return total;
}
template<typename T>
void read(T&x)
{
bool Neg=false;
char c;
for(c= getchar();c<'0'||c>'9';c=getchar())
if(c=='-') Neg =!Neg;
x = c-'0';
for (c=getchar();c>='0'&&c<='9';c=getchar())
x=x*10+c-'0';
if(Neg&&x>0) x=-x;
}
ll findp(ll u)
{
return lab[u] < 0 ? u : lab[u] = findp(lab[u]);
}
bool hop(ll u, ll v)
{
u = findp(u);
v = findp(v);
if(u == v)return false;
if(lab[u] > lab[v])swap(u, v);
lab[u] += lab[v];
lab[v] = u;
return true;
}
string s;
void dfs(ll u, ll p)
{
d[u] = ++t;
for(ll i : adj[u])
{
ll v = a[i] + b[i] - u;
if(v == p)continue;
c[v] = i;
P[v][0] = u;
h[v] = h[u] + 1;
for(int i = 1; i <= 18; i ++)P[v][i] = P[P[v][i-1]][i-1];
dfs(v, u);
}
}
void cal(ll u, ll p)
{
for(ll i : adj[u])
{
ll v = a[i] + b[i] - u;
if(v == p)continue;
cal(v, u);
dp[u] += dp[v];
}
//cout << u <<" "<<dp[u] << '\n';
}
ll lca(ll u, ll v)
{
if(h[u] < h[v])swap(u, v);
ll log = log2(h[u]);
for(int i = log; i >= 0; i --)if(h[u] >= h[v] + (1<<i))u = P[u][i];
if(u == v)return u;
for(int i = log; i >= 0; i --)
{
if(P[u][i] && P[u][i] != P[v][i])
{
u = P[u][i];
v = P[v][i];
}
}
return P[u][0];
}
void sol()
{
cin >> n >> m >> k;
for(int i = 1; i < n; i ++)
{
cin >> a[i] >> b[i];
adj[a[i]].pb(i);
adj[b[i]].pb(i);
}
h[1] = 1;
dfs(1, 0);
while(m -- > 0)
{
cin >> t;
vector<pll> kq;
for(int i = 1; i <= t; i ++)
{
ll u;
cin >> u;
++dp[u];
kq.pb({d[u], u});
}
sort(kq.begin(), kq.end());
for(int i = 0; i < t; i ++)
{
int j = (i+1)%t;
--dp[lca(kq[i].se, kq[j].se)];
//cout << kq[i].se <<" "<<kq[j].se << " "<<lca(kq[i].se, kq[j].se) << '\n';
}
}
cal(1, 0);
for(int i = 2; i <= n; i ++)if(dp[i] >= k)res.pb(c[i]);
sort(res.begin(), res.end());
cout << res.size() << '\n';
for(ll x : res)cout << x <<" ";
}
int main()
{
cin.tie(0);
cout.tie(0);
ios_base::sync_with_stdio(0);
#define task "testss"
if(fopen(task".inp", "r"))
{
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
int ntest = 1;
//cin >> ntest;
while(ntest -- > 0)
sol();
}
/*
10 4
5 4 3 2 -1 0 0 0 0 0
*/
