/* :) */
#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define ll long long
#define pll pair<ll, ll>
const int sz = 1e5+5;
vector<ll>g[sz];
ll in[sz], out[sz], par[sz], parent[sz][20], t;
map<pll, ll>mp, ans;
void dfs(ll v, ll p)
{
parent[v][0] = p;
for (ll i = 1; i<20; i++){
parent[v][i] = parent[parent[v][i-1]][i-1];
}
in[v] = ++t;
for (auto u : g[v]){
if (u != p){
par[u] = v;
dfs(u, v);
}
}
out[v] = ++t;
}
ll lca(ll x, ll y)
{
if (in[x] <= in[y] and out[y] <= out[x]) return x;
for (ll i = 19; i>=0; i--){
int p = parent[x][i];
if (!(in[p] <= in[y] and out[y] <= out[p])){
x = p;
}
}
return parent[x][0];
}
int main()
{
ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
ll n, m, k;
cin>>n>>m>>k;
for (ll i = 1; i<=n-1; i++){
ll u, v;
cin>>u>>v;
ans[{u, v}] = ans[{v, u}] = i;
g[u].push_back(v);
g[v].push_back(u);
}
in[0] = 0;
dfs(1, 0);
out[0] = ++t;
while (m--){
ll f, x, y;
cin>>f>>x;
set<pll>s;
for (ll i = 2; i<=f; i++){
cin>>y;
ll Y = y;
ll l = lca(x, y);
while (x != l){
if (par[x] > x) s.insert({x, par[x]});
else s.insert({par[x], x});
x = par[x];
}
while (y != l){
if (par[y] > y) s.insert({y, par[y]});
else s.insert({par[y], y});
y = par[y];
}
x = Y;
}
for (auto i : s){
mp[{i.first, i.second}]++;
}
}
vector<ll>v;
for (auto i : mp){
if (i.second >= k){
v.push_back(ans[{i.first.first, i.first.second}]);
}
}
cout<<v.size()<<endl;
for (ll i = 0; i<v.size(); i++){
cout<<v[i]<<' ';
}
}
