public static void main ( String [ ] args ) {
  int n , m ;
  int bulbs ;
  Scanner sc = new Scanner ( System . in ) ;
  Set < Integer > onBulbs = new HashSet < > ( ) ;
  n = sc . nextInt ( ) ;
  m = sc . nextInt ( ) ;
  for ( int i = 1 ;
  i <= n ;
  i ++ ) {
    bulbs = sc . nextInt ( ) ;
    int temp ;
    for ( int j = 1 ;
    j <= bulbs ;
    j ++ ) {
      temp = sc . nextInt ( ) ;
      onBulbs . add ( temp ) ;
    }
  }
  if ( m == onBulbs . size ( ) ) System . out . println ( "YES" ) ;
  else System . out . println ( "NO" ) ;
}

public static void main ( String [ ] args ) { int n , m ; int bulbs ; Scanner sc = new Scanner ( System . in ) ; Set < Integer > onBulbs = new HashSet < > ( ) ; n = sc . nextInt ( ) ; m = sc . nextInt ( ) ; for ( int i = 1 ; i <= n ; i ++ ) { bulbs = sc . nextInt ( ) ; int temp ; for ( int j = 1 ; j <= bulbs ; j ++ ) { temp = sc . nextInt ( ) ; onBulbs . add ( temp ) ; } } if ( m == onBulbs . size ( ) ) System . out . println ( " YES " ) ; else System . out . println ( " NO " ) ; }
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