#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5+10;
typedef pair<int, int> pii;
int chain[maxn], head[maxn], ind[maxn], back[maxn], cc, pp;
int sz[maxn], nivel[maxn], pai[maxn], n;
int freq[maxn], mark[maxn], aux;
vector<int> grafo[maxn], tree[4*maxn];
void dfs(int u, int p)
{
sz[u] = 1;
for (auto v: grafo[u])
{
if (v == p) continue;
nivel[v] = nivel[u]+1, pai[v] = u;
dfs(v, u);
sz[u] += sz[v];
}
}
void hld(int u)
{
if (!head[cc]) head[cc] = u;
chain[u] = cc, ind[u] = ++pp, back[pp] = u;
int maior = -1, child = -1;
for (auto v: grafo[u])
if (v != pai[u] && sz[v] > maior)
maior = sz[v], child = v;
if (child != -1) hld(child);
for (auto v: grafo[u])
if (v != pai[u] && v != child)
cc++, hld(v);
}
int lca(int u, int v)
{
while (chain[u] != chain[v])
{
if (nivel[head[chain[u]]] > nivel[head[chain[v]]])
u = pai[head[chain[u]]];
else
v = pai[head[chain[v]]];
}
return (nivel[u] > nivel[v] ? v : u);
}
void upd(int node, int l, int r, int a, int b, int v)
{
if (l > b || r < a) return;
if (l >= a && r <= b)
{
tree[node].push_back(v);
return;
}
int mid = (l+r)>>1;
upd(2*node, l, mid, a, b, v); upd(2*node+1, mid+1, r, a, b, v);
}
void upd_path(int u, int v, int it)
{
while (true)
{
if (chain[u] == chain[v])
{
if (u != v) upd(1, 1, n, ind[v]+1, ind[u], it);
return;
}
upd(1, 1, n, ind[head[chain[u]]], ind[u], it);
u = pai[head[chain[u]]];
}
}
void solve(int node, int l, int r)
{
for (auto x: tree[node])
{
if (!mark[x]) aux++;
mark[x]++;
}
if (l == r) freq[back[l]] = aux;
if (l != r)
{
int mid = (l+r)>>1;
solve(2*node, l, mid); solve(2*node+1, mid+1, r);
}
for (auto x: tree[node])
{
mark[x]--;
if (!mark[x]) aux--;
}
}
int main(void)
{
ios::sync_with_stdio(false); cin.tie(0);
int m, k;
cin >> n >> m >> k;
map<pii, int> mp;
for (int i = 1; i < n; i++)
{
int u, v;
cin >> u >> v;
grafo[u].push_back(v); grafo[v].push_back(u);
mp[{u, v}] = mp[{v, u}] = i;
}
dfs(1, 0);
hld(1);
for (int i = 1; i <= m; i++)
{
int s, u;
cin >> s >> u;
for (int j = 2; j <= s; j++)
{
int v, low;
cin >> v;
low = lca(u, v);
upd_path(u, low, i); upd_path(v, low, i);
}
}
solve(1, 1, n);
int qtd = 0;
vector<int> ans;
for (int i = 1; i <= n; i++)
{
if (freq[i] >= k)
{
qtd++;
ans.push_back(mp[{i, pai[i]}]);
}
}
sort(ans.begin(), ans.end());
cout << qtd << "\n";
if (qtd)
{
cout << ans[0];
for (int i = 1; i < ans.size(); i++)
cout << " " << ans[i];
cout << "\n";
}
}
