#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef long long ll;
typedef pair<ll,ll> pll;
typedef tuple<int,int,int> ti;
typedef unsigned long long ull;
typedef long double ld;
typedef vector<ll> vll;
typedef pair<ld,ld> pld;
#define pb push_back
#define popb pop_back()
#define pf push_front
#define popf pop_front
#define ff first
#define ss second
#define MOD (ll)(1000000007)
#define INF (ll) (1e18)
#define all(v) (v).begin(),(v).end()
const int nx[8] = {0, 0, 1, -1,1,1,-1,-1}, ny[8] = {1, -1, 0, 0,1,-1,1,-1}; //East, West, South, North+
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;}
ll lcm(ll a, ll b){return (a / gcd(a, b)) * b;}
////////////******SOLUTION******\\\\\\\\\\\
const int MAX_N = 1e5 + 4;
int n, m, k;
vector<pii> edges;
vi adj[MAX_N];
int depth[MAX_N];
vi edsort;
map<pii,int> key;
bool comp(int a, int b)
{
return depth[a] < depth[b];
}
set<int> co;
set<int> ans;
set<pii> ens;
int dfs(int node, int par)
{
int rep= co.count(node) == 0? 0: 1;
for(auto e: adj[node])
{
if(e == par)
continue;
if(dfs(e,node))
{
rep = 1;
ans.insert(key[{min(e,node),max(e,node)}]);
}
}
return rep;
}
void task4()
{
for(int i = 1; i<=m; i ++)
{
int s; cin >> s;
for(int u = 1; u <= s; u ++)
{
int x; cin >> x;
co.insert(x);
}
dfs(*(co.begin()),-1);
co.clear();
}
cout << ans.size() << '\n';
for(auto e: ans)
cout << e << ' ';
}
void solve()
{
cin >> n >> m >> k;
int maxt = 0;
memset(depth,-1,sizeof(depth));
for(int i = 1; i<n; i++)
{
int a, b;
cin >> a >> b;
key[{min(a,b),max(a,b)}] = i;
adj[a].pb(b);
adj[b].pb(a);
maxt = max(maxt, max((int)adj[a].size(),(int)adj[b].size()));
}
if(maxt > 2)
{
task4();
return ;
}
int root = 1;
for(int i= 1; i <=n; i ++)
{
if(adj[i].size() == 1)
{
root = i;
break;
}
}
queue<pii> q;
q.push({root,0});
while(!q.empty())
{
int node = q.front().ff;
int d= q.front().ss;
q.pop();
depth[node]= d;
for(auto e: adj[node])
{
if(depth[e] != -1)
continue;
q.push({e,d+1});
depth[e] = d + 1;
edsort.pb(key[{min(node,e),max(node,e)}]);
}
}
int dom[n];
memset(dom,0,sizeof(dom));
for(int minis = 1; minis <= m; minis ++)
{
vi nei;
int s; cin>> s;
for(int u = 1; u <= s; u ++)
{
int x; cin >> x;
nei.pb(x);
}
//cout << "this far" << endl;
sort(all(nei),comp);
int u = depth[nei[0]];
int v = depth[nei[s-1]];
for(int j = u; j < v; j ++)
dom[j]++;
}
for(int i = 0; i < n-1; i ++)
{
if(dom[i] >= k)
ans.insert(edsort[i]);
}
cout << ans.size() << '\n';
for(auto e: ans)
cout << e << ' ';
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int tt = 1;
while(tt--)
solve();
}
/* 6 3 2
2 5 1 5 1 3 6 3 6 4
3 2 3 4
2 1 6
3 1 6 4
*/
/*
6 3 3
1 3
2 3
3 4
6 4
4 5
2 1 3
2 6 3
2 3 2
*/
