#include <bits/stdc++.h>
#define int long long
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define sc second
///#define endl "\n"
#define pii pair<int,int>
using namespace std;
const int MAXN = 1e5+5;
const int mod7 = 1e9+7;
const long long inf = 1e18;
const int lg = 18;
int up[MAXN][lg];
int dist[MAXN];
int tin[MAXN];
int tout[MAXN];
int cnt[MAXN];
int t = 1;
int n,m,k;
vector<vector<int>> graf(MAXN);
void dfs(int nod, int p, int d)
{
dist[nod] = d;
up[nod][0] = p;
tin[nod] = t++;
for(auto x: graf[nod])if(x!=p)dfs(x,nod,d+1);
tout[nod] = t++;
}
void fillUp()
{
for(int i=1; i<lg; i++)
{
for(int j=1; j<=n; j++)
{
up[j][i] = up[up[j][i-1]][i-1];
}
}
}
int lca(int u,int v)
{
if(u == v)return u;
if(tin[u] < tin[v] && tout[u] > tout[v])return u;
if(tin[u] > tin[v] && tout[u] < tout[v])return v;
for(int i=lg-1; i>=0; i--)
{
int probaj = up[v][i];
if(!(tin[probaj] < tin[u] && tout[probaj] > tout[u]))v = probaj;
}
return up[v][0];
}
int dfs2(int nod, int p)
{
for(auto x:graf[nod])
{
if(x==p)continue;
cnt[nod] += dfs2(x,nod);
}
return cnt[nod];
}
signed main()
{
ios_base::sync_with_stdio(false),cin.tie(0), cout.tie(0);
int tt=1;
//cin >> tt;
while(tt--)
{
cin >> n >> m>> k;
vector<pii>svi_putevi(n-1);
for(int i=0; i<n-1; i++)
{
int a,b;cin >> a >> b;
svi_putevi[i].fi = a;
svi_putevi[i].sc = b;
graf[a].pb(b);
graf[b].pb(a);
}
dfs(1,1,0);
fillUp();
for(int i=0; i<m; i++)
{
int x;cin >> x;
vector<pii> v(x);
for(int j=0; j<x; j++)
{
cin >> v[j].sc;
v[j].fi = tin[v[j].sc];
}
sort(all(v));
reverse(all(v));
//for(auto x: v)cout << x.sc << " "; cout << endl;
int cale = lca(v[0].sc, v[1].sc);
cnt[v[0].sc] ++;
cnt[v[1].sc] ++;
cnt[cale] -=2;
for(int j=2; j<x; j++)
{
cnt[cale]++;
cnt[v[j].sc]++;
cale = lca(cale, v[j].sc);
cnt[cale]-=2;
}
}
dfs2(1,1);
int rez = 0;
for(int i=1; i<=n; i++)if(cnt[i]>=k)rez++;
cout << rez << endl;
for(int i=0; i<n-1; i++)
{
int a = svi_putevi[i].fi;
int b = svi_putevi[i].sc;
if(dist[a] > dist[b])swap(a,b);
if(cnt[b] >= k)cout << i + 1 << " ";
}
}
}
