#include<bits/stdc++.h>
#define endl '\n'
#define pb push_back
using namespace std;
const int maxn = 1e5 + 10;
void speed()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
}
int n, m, k;
vector < pair < int, int > > g[maxn];
int p[maxn], pindex[maxn], depth[maxn];
void dfs0(int beg, int from)
{
p[beg] = from;
depth[beg] = depth[from] + 1;
for (auto &[nb, id]: g[beg])
{
if(nb == from)continue;
dfs0(nb, beg);
pindex[nb] = id;
}
}
int jump[maxn][20];
int moveup(int v, int x)
{
for (int i = 0; i < 20; ++ i)
if(x & (1 << i))v = jump[v][i];
return v;
}
int lca(int u, int v)
{
//cout << "getting lca " << u << " and " << v << endl;
if(depth[u] < depth[v])swap(u, v);
int diff = depth[u] - depth[v];
u = moveup(u, diff);
// cout << "* " << u << " " << v << endl;
if(u == v)return u;
for (int i = 19; i>= 0; -- i)
{
int newu = jump[u][i];
int newv = jump[v][i];
if(newu && newv && newv != newu)
{
u = newu;
v = newv;
}
}
return p[u];
}
set < int > st[maxn], fi[maxn];
int uni[maxn], ans[maxn];
set < int > keep[maxn];
bool cmp(int a, int b)
{
return (keep[a].size() > keep[b].size());
}
void dfs(int beg, int from)
{
set < int > res;
vector < int > u;
for (auto &[nb, index]: g[beg])
{
if(nb == from)continue;
u.pb(nb);
dfs(nb, beg);
}
if(u.size() > 0)
{
sort(u.begin(), u.end(), cmp);
swap(res, keep[u[0]]);
for (int i = 1; i < u.size(); ++ i)
{
int nb = u[i];
for (auto key: keep[nb])
res.insert(key);
}
}
for (auto key: st[beg])
res.insert(key);
for (auto key: fi[beg])
res.erase(key);
ans[pindex[beg]] = res.size();
swap(res, keep[beg]);
}
int main()
{
speed();
cin >> n >> m >> k;
for (int i = 1; i < n; ++ i)
{
int uu, vv;
cin >> uu >> vv;
g[uu].pb(make_pair(vv, i));
g[vv].pb(make_pair(uu, i));
}
dfs0(1, 0);
for (int i = 1; i <= n; ++ i)
jump[i][0] = p[i];
for (int j = 1; j < 20; ++ j)
{
for (int i = 1; i <= n; ++ i)
jump[i][j] = jump[jump[i][j-1]][j-1];
}
for (int i = 1; i <= m; ++ i)
{
int cnt;
cin >> cnt;
vector < int > s;
int last;
cin >> last;
s.pb(last);
for (int j = 1; j < cnt; ++ j)
{
int v;
cin >> v;
s.pb(v);
last = lca(last, v);
}
for (auto v: s)
st[v].insert(i);
fi[last].insert(i);
// cout << "lca is "<<last << endl;
}
dfs(1, 0);
vector < int > make;
for (int i = 1; i < n; ++ i)
{
if(ans[i] >= k)make.pb(i);
}
cout << make.size() << endl;
for (auto x: make)
cout << x << " ";
cout << endl;
return 0;
}
