#include<bits/stdc++.h>
using namespace std ;
typedef long long ll ;
typedef unsigned long long ull ;
#define fi first
#define se second
// mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
const int MAXN = 1e5 + 7 ;
const int LOG = 17 ;
int n , m , k ;
vector < pair < int , int > > v[ MAXN ] ;
int prv_id[ MAXN ] ;
int lvl[ MAXN ] ;
int LCA[ MAXN ][ LOG ] ;
int st[ MAXN ] , en[ MAXN ] ;
int add[ MAXN ] , tp ;
void init ( int x , int prv ) {
st[ x ] = ++ tp ;
for ( int i = 1 ; i < LOG ; ++ i ) {
LCA[ x ][ i ] = LCA[ LCA[ x ][ i - 1 ] ][ i - 1 ] ;
}
for ( auto [ y , id ] : v[ x ] ) {
if ( y == prv ) { continue ; }
prv_id[ y ] = id ;
LCA[ y ][ 0 ] = x ;
lvl[ y ] = lvl[ x ] + 1 ;
init ( y , x ) ;
}
en[ x ] = tp ;
}
int get_lca ( int x , int y ) {
for ( int i = LOG - 1 ; i >= 0 ; -- i ) {
if ( lvl[ x ] - ( 1 << i ) >= lvl[ y ] ) {
x = LCA[ x ][ i ] ;
}
if ( lvl[ y ] - ( 1 << i ) >= lvl[ x ] ) {
y = LCA[ y ][ i ] ;
}
}
for ( int i = LOG - 1 ; i >= 0 ; -- i ) {
if ( LCA[ x ][ i ] != LCA[ y ][ i ] ) {
x = LCA[ x ][ i ] , y = LCA[ y ][ i ] ;
}
}
if ( x != y ) { x = LCA[ x ][ 0 ] ; }
return x ;
}
bool is_anc ( int up , int down ) {
return ( st[ up ] <= st[ down ] && en[ down ] <= en[ up ] ) ;
}
int aux[ 2 * MAXN ] ;
vector < int > ans ;
void dfs ( int x , int prv ) {
for ( auto [ y , id ] : v[ x ] ) {
if ( y == prv ) { continue ; }
dfs ( y , x ) ;
add[ x ] += add[ y ] ;
}
}
void solve ( ) {
cin >> n >> m >> k ;
for ( int i = 1 , x , y ; i < n ; ++ i ) {
cin >> x >> y ;
v[ x ].push_back ( { y , i } ) ;
v[ y ].push_back ( { x , i } ) ;
}
init ( 1 , -1 ) ;
stack < int > s ;
auto cmp = [ & ] ( int x , int y ) {
return ( st[ x ] < st[ y ] ) ;
};
while ( m -- ) {
int sz ; cin >> sz ;
for ( int i = 1 ; i <= sz ; ++ i ) {
cin >> aux[ i ] ;
}
sort ( aux + 1 , aux + sz + 1 , cmp ) ;
while ( s.empty ( ) == false ) { s.pop ( ) ; }
tp = sz ;
for ( int i = 1 ; i < sz ; ++ i ) {
aux[ ++ tp ] = get_lca ( aux[ i ] , aux[ i + 1 ] ) ;
}
sz = tp ;
sort ( aux + 1 , aux + sz + 1 , cmp ) ;
s.push ( aux[ 1 ] ) ;
for ( int i = 2 ; i <= sz ; ++ i ) {
while ( is_anc ( s.top ( ) , aux[ i ] ) == false ) {
int root = get_lca ( s.top ( ) , aux[ i ] ) ;
++ add[ s.top ( ) ] , -- add[ root ] ;
s.pop ( ) ;
}
s.push ( aux[ i ] ) ;
}
while ( 1 ) {
int leaf = s.top ( ) ; s.pop ( ) ;
if ( s.empty ( ) == true ) { break ; }
int root = s.top ( ) ;
++ add[ leaf ] , -- add[ root ] ;
}
}
dfs ( 1 , -1 ) ;
for ( int i = 2 ; i <= n ; ++ i ) {
if ( add[ i ] >= k ) {
ans.push_back ( prv_id[ i ] ) ;
}
}
sort ( ans.begin ( ) , ans.end ( ) ) ;
int sz = ans.size ( ) ;
cout << sz << "\n" ;
for ( auto x : ans ) {
cout << x << " " ;
}
cout << "\n" ;
}
int main ( ) {
ios_base :: sync_with_stdio ( false ) ;
cin.tie ( NULL ) ;
int t = 1 ; // cin >> t ;
while ( t -- ) { solve ( ) ; }
return 0 ;
}
