#pragma GCC optimize("Ofast,unroll-loops")
#include<bits/stdc++.h>
//#define int long long
//#define ll long long
#define down cout<<'\n';
#define debug cout<<" cucuucucuuu",down
#define NHP ios_base::sync_with_stdio(0);cout.tie(0);cin.tie(0);
#define modwwe int t;cin>>t; while(t--)
#define bit(i,j) (i>>j&1)
#define sobit(a) __builtin_popcountll(a)
#define task "test"
#define fin(x) freopen(x".inp","r",stdin)
#define fou(x) freopen(x".ans","w",stdout)
#define pb push_back
#define checktime cerr << (double)clock() / CLOCKS_PER_SEC * 1000 << " ms";
using namespace std;
#define getchar_unlocked getchar
inline int scan()
{
char c = getchar_unlocked();
int x = 0;
while(c<'0'||c>'9')
{
c=getchar_unlocked();
}
while(c>='0'&&c<='9')
{
x=(x<<1)+(x<<3)+c-'0';
c=getchar_unlocked();
}
return x;
}
void phongbeo();
const int inf=1e9;
const int mod2=998244353;
const int mod1=998244353;
struct icd
{
long double a;
int b;
};
struct ib
{
int a;
int b;
};
struct ic
{
int a,b,c;
};
struct id
{
int a,b,c,d;
};
struct ie
{
int a,b,c,d,e;
};
int n,m,s1,s2,s4,s3,sf,k,s5,s6,mx,s7,s8,s9,mx2,res,dem2=0,dem=0,s33,dem3,dem4,l,r,mid,l2,r2,center;
int i,s10,s12;
int kk;
int el=29;
main()
{
#ifndef ONLINE_JUDGE
// fin(task),fou(task);
#endif
NHP
/// cin>>s1;
//modwwe
phongbeo(),down
//checktime
}
int dp[100001];
vector<ib> v[100001];
int depth[100001];
int st[17][100001];
vector<int> v2,v3;
int in[100001];
int lca(int u,int v)
{
if(depth[u]>depth[v])swap(u,v);
int ss=depth[v]-depth[u];
for(int j=0; j<17; j++)
{
if(bit(ss,j))
{
v=st[j][v];
}
}
if(v==u) return v;
for(int j=16; j>=0; --j)
{
if(st[j][u]!=st[j][v])
{
u=st[j][u];
v=st[j][v];
}
}
return st[0][v];
}
void dfs(int x,int y)
{ st[0][x]=y;
in[x]=++dem;
depth[x]=depth[y]+1;
for(auto f:v[x])
if(f.a!=y)
dfs(f.a,x);
}
void dfs2(int x,int y)
{
for(auto f:v[x])
if(f.a!=y){
dfs2(f.a,x),dp[x]+=dp[f.a];
if(dp[f.a]>=k)v3.pb(f.b);
}
}
bool cmp(int x,int y)
{
return in[x]<in[y];
}
void phongbeo()
{
cin>>n>>m>>k;
for(int i=1;i<n;i++)
cin>>l>>r,v[l].pb({r,i}),v[r].pb({l,i});
dfs(1,0);
for(int i=1;i<17;i++)
for(int j=1;j<=n;j++)
st[i][j]=st[i-1][st[i-1][j]];
while(m--)
{
cin>>l;
v2.clear();
for(int i=1;i<=l;i++)
{
cin>>r;
v2.pb(r);
}
sort(v2.begin(),v2.end(),cmp);
for(int i=0;i<l;i++)
{
if(i==0)
{
s2=lca(v2[0],v2.back());
dp[v2[0]]++;
dp[s2]--;
}
else
{
s2=lca(v2[i],v2[i-1]);
dp[v2[i]]++;
dp[s2]--;
}
}
}
dfs2(1,0);
sort(v3.begin(),v3.end());
cout<<v3.size(),down
for(auto x:v3)
cout<<x<<" ";
}
