#include<bits/stdc++.h>
using namespace std;
#define task "test"
#define pb push_back
#define fi first
#define se second
#define for1(i,j,k) for(int i=j;i<=k;i++)
#define for2(i,j,k) for(int i=j;i>=k;i--)
#define for3(i,j,k,l) for(int i=j;i<=k;i+=l)
#define bit(n,i) ((n>>i)&1)
#define all(x) x.begin(),x.end()
//#pragma GCC optimize("O2,unroll-loops")
//#pragma GCC target("avx,avx2,bmi,bmi2,sse,sse2,sse3,ssse3,sse4,popcnt")
#define int long long
typedef long long ll;
typedef pair<int,int> pii;
typedef double ld;
typedef pair<ld,ld> pdd;
typedef pair<ll,ll> pll;
const ll maxn=1e5+2;
const ll inf=1e18;
const ll mod=1e9+7;
const ll base=311;
int n,m,k,ans;
vector<int> adj[maxn],res;
int in[maxn],out[maxn],Time,par[maxn][20],sum[maxn];
void dfs(int u,int pre)
{
in[u]=++Time;
par[u][0]=pre;
for (int i=1;i<=17;i++)
{
par[u][i]=par[par[u][i-1]][i-1];
}
for (int v: adj[u])
{
if (v==pre) continue;
dfs(v,u);
}
out[u]=Time;
}
inline bool is_ancestor(int u,int v)
{
return (in[u]<=in[v] && out[v]<=out[u]);
}
int lca(int u,int v)
{
if (is_ancestor(u,v)) return u;
if (is_ancestor(v,u)) return v;
for (int i=17;i>=0;i--)
{
if (!is_ancestor(par[u][i],v)) u=par[u][i];
}
return par[u][0];
}
int d[maxn],kkk[maxn];
void dfs1(int u,int pre)
{
for (int v:adj[u])
{
if (v==pre) continue;
dfs1(v, u);
sum[u]+=sum[v];
}
if (sum[u]>=k)
{
ans++;
res.pb(kkk[u]);
}
//cout <<"ww "<< u<< ' '<<sum[u]<<'\n';
}
vector<int> a[maxn];
pii ed[maxn];
void sol()
{
cin >> n>> m>> k;
for (int i=1;i<n;i++)
{
int u,v;cin >> u>>v;
adj[u].pb(v);
adj[v].pb(u);
ed[i]={u,v};
}
dfs(1,1);
for (int i=1;i<n;i++)
{
if (is_ancestor(ed[i].fi,ed[i].se))
{
kkk[ed[i].se]=i;
}
else kkk[ed[i].fi]=i;
}
for (int i=1;i<=m;i++)
{
cin >> d[i];
for (int j=1;j<=d[i];j++)
{
int x;cin >> x;
a[i].pb(x);
sum[x]++;
}
sort(all(a[i]),[](int u,int v){
return in[u]< in[v];
});
int hi=a[i][d[i]-1];
for (int j=0;j<d[i]-1;j++)
{
hi=lca(hi,a[i][j]);
sum[lca(a[i][j],a[i][j+1])]--;
}
sum[hi]--;
}
dfs1(1,1);
cout << ans<<'\n';
sort(all(res));
for (int v: res) cout << v<<' ';
}
int32_t main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
if (fopen(task".inp","r"))
{
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
// int theta; cin >> theta;
int t=1;//cin >> t;
while (t--) sol();
}
