#include <bits/stdc++.h>
#define SPED \
ios_base::sync_with_stdio(false); \
cin.tie(0); \
cout.tie(0);
#define endl "\n"
#define fi first
#define se second
#define lint long long
#define fami signed
#define lore main
#define freefire freopen
const lint INF = 1e15;
using namespace std;
int n, k, m, entry[100005], contain[100005], timedfs, up[20][100005], depth[100005], dp[100005];
vector<int> adj[100005];
pair<int, int> edge[100005];
void dfs(int now, int par)
{
up[0][now] = par;
entry[now] = ++timedfs;
for (auto i : adj[now])
{
if (i == par)
continue;
depth[i] = depth[now] + 1;
dfs(i, now);
}
}
void build()
{
for (int i = 1; i < 20; i++)
for (int j = 1; j <= n; j++)
up[i][j] = up[i - 1][up[i - 1][j]];
}
int kth(int x, int k)
{
for (int i = 0; i < 20; i++)
if ((k >> i) & 1)
x = up[i][x];
return x;
}
int lca(int l, int r)
{
if (depth[l] > depth[r])
swap(l, r);
r = kth(r, depth[r] - depth[l]);
if (l == r)
return l;
for (int i = 19; i >= 0; i--)
{
if (up[i][l] != up[i][r])
{
l = up[i][l];
r = up[i][r];
}
}
return up[0][l];
}
void dfs1(int now, int par)
{
for (auto i : adj[now])
{
if (i == par)
continue;
dfs1(i, now);
dp[now] += dp[i];
}
}
bool cmp(int jack, int mck)
{
return entry[jack] < entry[mck];
}
fami lore()
{
// freopen("SUADUONG.inp", "r", stdin);
// freopen("SUADUONG.out", "w", stdout);
SPED;
cin >> n >> m >> k;
for (int i = 1; i < n; i++)
{
int l, r;
cin >> l >> r;
adj[l].emplace_back(r);
adj[r].emplace_back(l);
edge[i] = {l, r};
}
dfs(1, 0);
build();
for (int i = 1; i < n; i++)
{
auto [u, v] = edge[i];
if (depth[u] > depth[v])
contain[u] = i;
else
contain[v] = i;
}
for (int i = 1; i <= m; i++)
{
int x;
cin >> x;
int a[x + 1];
for (int j = 1; j <= x; j++)
{
cin >> a[j];
++dp[a[j]];
}
int niga = a[1];
for (int i = 2; i <= x; i++)
niga = lca(niga, a[i]);
sort(a + 1, a + 1 + x, cmp);
for (int i = 2; i <= x; i++)
dp[lca(a[i - 1], a[i])] -= 1;
dp[niga] -= 1;
}
dfs1(1, 0);
vector<int> suggest;
for (int i = 2; i <= n; i++)
if (dp[i] >= k)
suggest.emplace_back(contain[i]);
sort(suggest.begin(), suggest.end());
cout << suggest.size() << endl;
for (auto z : suggest)
cout << z << " ";
}
// Let your soul wander where dreams are born.
