#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ff first
#define ss second
#define ll int64_t
#define ld long double
#define nl cout<<"\n"
#define i128 __int128_t
#define all(v) v.begin(),v.end()
#define mset(a,v) memset((a),(v),sizeof(a))
#define forn(i,a,b) for(int64_t i=int64_t(a);i<int64_t(b);++i)
#define forb(i,a,b) for(int64_t i=int64_t(a);i>=int64_t(b);--i)
#define fastio() ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define mod 1'000'000'007
#define mod2 998'244'353
#define inf 1'000'000'000'000'007
#define pi 3.14159265358979323846
template<class key,class cmp=std::less<key>>
using ordered_set=tree<key,null_type,cmp,rb_tree_tag,tree_order_statistics_node_update>;
template<class L,class R> ostream& operator<<(ostream& out,pair<L,R> &p) {return out<<"("<<p.ff<<", "<<p.ss<<")";}
template<class T> ostream& operator<<(ostream& out,vector<T> &v) {out<<"[";for(auto it=v.begin();it!=v.end();++it){if(it!=v.begin())out<<", ";out<<*it;}return out<<"]";}
template<class T> ostream& operator<<(ostream& out,deque<T> &v) {out<<"[";for(auto it=v.begin();it!=v.end();++it){if(it!=v.begin())out<<", ";out<<*it;}return out<<"]";}
template<class T> ostream& operator<<(ostream& out,set<T> &s) {out<<"{";for(auto it=s.begin();it!=s.end();++it){if(it!=s.begin())out<<", ";out<<*it;}return out<<"}";}
template<class T> ostream& operator<<(ostream& out,ordered_set<T> &s) {out<<"{";for(auto it=s.begin();it!=s.end();++it){if(it!=s.begin())out<<", ";out<<*it;}return out<<"}";}
template<class L,class R> ostream& operator<<(ostream& out,map<L,R> &m) {out<<"{";for(auto it=m.begin();it!=m.end();++it){if(it!=m.begin())out<<", ";out<<*it;}return out<<"}";}
void dbg_out() {cerr<<"]\n";}
template<typename Head,typename... Tail>
void dbg_out(Head H,Tail... T) {cerr<<H;if(sizeof...(Tail))cerr<<", ";dbg_out(T...);}
#ifdef LOCAL
#define dbg(...) cerr<<"["<<#__VA_ARGS__<<"] = [",dbg_out(__VA_ARGS__)
#else
#define dbg(...)
#endif
//---------------------------------mars4---------------------------------
class LCA
{
ll n;
ll N;
ll K;
void dfs(ll cur,ll prev,vector<vector<ll>> &v)
{
ind[cur]=(ll)euler.size();
euler.push_back(cur);
euler_depth.push_back(depth[cur]);
for(ll i:v[cur])
{
if(i!=prev)
{
depth[i]=depth[cur]+1;
dfs(i,cur,v);
euler.push_back(cur);
euler_depth.push_back(depth[cur]);
}
}
}
void build()
{
N=(ll)euler_depth.size();
K=64-__builtin_clzll(N);
st=vector<vector<ll>>(N,vector<ll>(K));
logN=vector<ll>(N+1);
for(int i=2;i<=N;i++)
{
logN[i]=logN[i/2]+1;
}
for(int i=1;i<N;i++)
{
st[i][0]=i;
}
for(int j=1;j<=K;j++)
{
for(int i=0;i+(1ll<<j)<=N;i++)
{
if(euler_depth[st[i][j-1]]<euler_depth[st[i+(1ll<<(j-1))][j-1]])
{
st[i][j]=st[i][j-1];
}
else
{
st[i][j]=st[i+(1ll<<(j-1))][j-1];
}
}
}
}
public:
vector<ll> euler;
vector<ll> ind;
vector<ll> depth;
vector<ll> euler_depth;
vector<vector<ll>> st;
vector<ll> logN;
void init(vector<vector<ll>> &v,ll root=0)
{
ll n=(ll)v.size();
ind=vector<ll>(n);
depth=vector<ll>(n);
dfs(root,-1,v);
build();
}
ll lca(ll u,ll v)
{
if(ind[u]>ind[v])
{
swap(u,v);
}
ll l=ind[u];
ll r=ind[v];
ll j=logN[r-l+1];
if(euler_depth[st[l][j]]<euler_depth[st[r-(1ll<<j)+1][j]])
{
return euler[st[l][j]];
}
else
{
return euler[st[r-(1ll<<j)+1][j]];
}
}
ll dist(ll u,ll v)
{
return depth[u]+depth[v]-2*depth[lca(u,v)];
}
};
class SegtreeSum
{
ll N;
vector<ll> segtree;
vector<ll> lazy;
ll _build(vector<ll> &a,ll st,ll ed,ll i=1)
{
if(st==ed)
return segtree[i]=a[st];
ll mid=(st+ed)>>1;
return segtree[i]=_build(a,st,mid,i<<1)+_build(a,mid+1,ed,i<<1|1);
}
void _push(ll st,ll ed,ll val,ll i)
{
if(st^ed)
{
lazy[i<<1]+=val;
lazy[i<<1|1]+=val;
}
}
void _update(ll st,ll ed,ll l,ll r,ll val,ll i=1)
{
if(lazy[i])
{
segtree[i]+=lazy[i]*(ed-st+1);
_push(st,ed,lazy[i],i);
lazy[i]=0;
}
if(st>ed or st>r or ed<l)
return;
if(st>=l and ed<=r)
{
segtree[i]+=val*(ed-st+1);
_push(st,ed,val,i);
return;
}
ll mid=(st+ed)>>1;
_update(st,mid,l,r,val,i<<1);
_update(mid+1,ed,l,r,val,i<<1|1);
segtree[i]=segtree[i<<1]+segtree[i<<1|1];
}
ll _query(ll st,ll ed,ll l,ll r,ll i=1)
{
if(lazy[i])
{
segtree[i]+=lazy[i]*(ed-st+1);
_push(st,ed,lazy[i],i);
lazy[i]=0;
}
if(st>ed or st>r or ed<l)
return 0;
if(st>=l and ed<=r)
return segtree[i];
ll mid=(st+ed)>>1;
return _query(st,mid,l,r,i<<1)+_query(mid+1,ed,l,r,i<<1|1);
}
// for prefix sum
ll _first_element_atleast_x(ll st,ll ed,ll l,ll r,ll val,ll i=1)
{
if(lazy[i])
{
segtree[i]+=lazy[i]*(ed-st+1);
_push(st,ed,lazy[i],i);
lazy[i]=0;
}
if(st>ed or st>r or ed<l or segtree[i]<val)
return -1;
if(st==ed)
return st;
ll mid=(st+ed)>>1;
ll ind=_first_element_atleast_x(st,mid,l,r,val,i<<1);
if(ind==-1)
ind=_first_element_atleast_x(mid+1,ed,l,r,val-segtree[i<<1],i<<1|1);
return ind;
}
public:
void init(ll n,ll val=0)
{
N=n;
segtree=vector<ll>(N<<2,val);
lazy=vector<ll>(N<<2);
}
void build(vector<ll> &a)
{
_build(a,0,N-1);
}
void update(ll l,ll r,ll val)
{
_update(0,N-1,l,r,val);
}
ll query(ll l,ll r)
{
return _query(0,N-1,l,r);
}
ll first_element_atleast_x(ll l,ll r,ll val)
{
return _first_element_atleast_x(0,N-1,l,r,val);
}
void clear()
{
segtree=vector<ll>(N<<2);
lazy=vector<ll>(N<<2);
}
};
class HLD
{
ll N;
ll timer;
void dfs_sz(ll cur,ll prev,vector<vector<ll>> &v)
{
child[cur]=1;
parent[cur]=prev;
for(ll i:v[cur])
{
if(i!=prev)
{
depth[i]=depth[cur]+1;
dfs_sz(i,cur,v);
child[cur]+=child[i];
}
}
}
void dfs_hld(ll cur,ll prev,ll top,vector<vector<ll>> &v)
{
timer++;
st[cur]=timer;
tp[cur]=top;
dn[top]=cur;
ll h_ind=-1,h_sz=-1;
for(ll i=0;i<(ll)v[cur].size();i++)
{
if(v[cur][i]!=prev)
{
if(child[v[cur][i]]>h_sz)
{
h_ind=i;
h_sz=child[v[cur][i]];
}
}
}
if(h_ind==-1)
{
ed[cur]=timer;
return;
}
swap(v[cur][0],v[cur][h_ind]);
dfs_hld(v[cur][0],cur,top,v);
for(ll i:v[cur])
{
if(i!=prev and i!=v[cur][0])
{
dfs_hld(i,cur,i,v);
}
}
ed[cur]=timer;
}
public:
vector<ll> child;
vector<ll> parent;
vector<ll> depth;
vector<ll> st;
vector<ll> ed;
vector<ll> tp;
vector<ll> dn;
// use segtree class
SegtreeSum s;
void init(vector<vector<ll>> &v,ll root=0)
{
N=(ll)v.size();
s.init(N);
child=vector<ll>(N);
parent=vector<ll>(N);
depth=vector<ll>(N);
st=vector<ll>(N);
ed=vector<ll>(N);
tp=vector<ll>(N);
dn=vector<ll>(N);
timer=-1;
dfs_sz(root,root,v);
dfs_hld(root,root,root,v);
}
void update(ll u,ll v)
{
while(tp[u]!=tp[v])
{
if(depth[tp[u]]<depth[tp[v]])
swap(u,v);
s.update(st[tp[u]],st[u],1);
u=parent[tp[u]];
}
if(depth[u]>depth[v])
swap(u,v);
s.update(st[u]+1,st[v],1);
}
ll query(ll u,ll v)
{
if(depth[u]>depth[v])
{
swap(u,v);
}
return s.query(st[v],st[v]);
}
};
vector<vector<ll>> v;
int main()
{
fastio();
ll z,n,m,t,k,i,j,l,d,h,r;
cin>>n>>m>>k;
v=vector<vector<ll>>(n);
vector<pair<ll,ll>> e(n-1);
forn(i,0,n-1)
{
cin>>l>>r;
l--,r--;
v[l].push_back(r);
v[r].push_back(l);
e[i]={l,r};
}
LCA lca;
lca.init(v);
HLD hld;
hld.init(v);
forn(i,0,m)
{
cin>>h;
vector<ll> nodes(h);
forn(j,0,h)
{
cin>>nodes[j];
nodes[j]--;
}
sort(all(nodes),[&](ll a,ll b){
return hld.st[a]<hld.st[b];
});
ll node=-1;
forn(j,0,h)
{
if(j==0)
{
node=nodes[j];
}
else
{
ll ancestor=lca.lca(node,nodes[j]);
if(ancestor==node)
{
hld.update(lca.lca(nodes[j-1],nodes[j]),nodes[j]);
}
else
{
hld.update(node,nodes[j]);
}
node=ancestor;
}
}
}
vector<ll> ans;
forn(i,0,n-1)
{
if(hld.query(e[i].ff,e[i].ss)>=k)
{
ans.push_back(i);
}
}
cout<<(ll)ans.size()<<"\n";
for(ll i:ans)
{
cout<<i+1<<" ";
}
nl;
cerr<<"\nTime elapsed: "<<1000*clock()/CLOCKS_PER_SEC<<"ms\n";
return 0;
}
