#include<bits/stdc++.h>
#define TASKNAME "lcm"
#define pb push_back
#define pli pair<int,int>
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL);
using namespace std;
using ll=long long;
const ll maxN=2e5+1;
const ll INF=-1e10;
const ll mod=1e9+7;
ll h[maxN],p[maxN],par[maxN][20];
ll LCA(ll u, ll v)
{
if(h[u]<h[v]) swap(u,v);
ll log=log2(h[u])+1;
for(int i=log;i>=0;i--)
{
if(h[par[u][i]]>=h[v]) u=par[u][i];
}
//cout << h[u]<<' '<< h[v]<<'\n';
if(u==v) return u;
for(int i=log;i>=0;i--)
{
if(par[u][i]!=par[v][i]) u=par[u][i],v=par[v][i];
}
return p[u];
}
vector<pli>g[maxN];
ll in[maxN],tg=0;
#define fi first
#define se second
ll id[maxN],idx[maxN];
void dfs(ll u=1,ll pp=0)
{
in[u]=++tg;
for(auto v1:g[u])
{
ll v=v1.fi;
ll i=v1.se;
if(v!=pp)
{
id[i]=v;
idx[v]=i;
p[v]=par[v][0]=u;
h[v]=h[u]+1;
for(int j=1;j<=18;j++) par[v][j]=par[par[v][j-1]][j-1];
dfs(v,u);
}
}
}
ll ans[maxN];
void dfs_lai(ll u=1,ll pp=0)
{
for(auto v1:g[u])
{
ll v=v1.fi;
ll i=v1.se;
if(v!=pp)
{
dfs_lai(v,u);
ans[u]+=ans[v];
}
}
}
bool cmp(ll x, ll y)
{
return in[x]<in[y];
}
void tang(ll u,ll pp)
{
ans[u]+=1;
ans[pp]-=1;
}
ll n,m,k;
ll tmp[maxN];
void solve()
{
cin >> n >> m >> k;
for(int i=1;i<n;i++)
{
ll u,v;
cin >> u >> v;
g[u].pb({v,i});
g[v].pb({u,i});
}
p[1]=1;
for(int i=0;i<=18;i++) par[1][i]=1;
dfs();
vector<ll> v;
for(int i=1;i<=m;i++)
{
ll sz;
v.clear();
cin>> sz;
for(int j=1;j<=sz;j++)
{
ll kk;
cin >>kk;
v.pb(kk);
}
stack<int> s;
sort(v.begin(),v.end(),cmp);
for(int j=0;j<v.size()-1;j++)
{
if(j==0)
{
ll x=LCA(v[0],v[1]);
tmp[1]=x;
tang(v[0],x);
tang(v[1],x);
}
else
{
ll x=LCA(v[j],v[j+1]);
ll u=v[j];
ll vv=v[j+1];
if(h[tmp[j]]>=h[x])
{
tang(tmp[j],x);
}
tang(vv,x);
if(h[tmp[j]]<h[x])
{
x=tmp[j];
}
tmp[j+1]=x;
}
}
}
dfs_lai();
vector<ll> ass;
for(int i=1;i<n;i++)
{
ll u=id[i];
if(ans[u]>=k)
{
ass.pb(i);
// cout << ans[u]<<'\n';
}
}
cout << ass.size()<<'\n';
for(auto z:ass) cout << z<< ' ';
//cout <<LCA(1,2) ;
}
int main()
{
fastio
//freopen(TASKNAME".IN","r",stdin);
//freopen(TASKNAME".OUT","w",stdout);
ll t=1;
//cin >> t;
while(t--)solve();
}
