public static void main ( String [ ] args ) {
  Scanner scanner = new Scanner ( System . in ) ;
  StringTokenizer tokenizer = new StringTokenizer ( scanner . nextLine ( ) ) ;
  int n = Integer . parseInt ( tokenizer . nextToken ( ) ) ;
  int m = Integer . parseInt ( tokenizer . nextToken ( ) ) ;
  boolean [ ] arr = new boolean [ m ] ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    StringTokenizer lineTok = new StringTokenizer ( scanner . nextLine ( ) ) ;
    int r = Integer . parseInt ( lineTok . nextToken ( ) ) ;
    for ( int j = 0 ;
    j < r ;
    j ++ ) {
      int i1 = Integer . parseInt ( lineTok . nextToken ( ) ) ;
      arr [ i1 - 1 ] = true ;
    }
  }
  boolean allMatch = true ;
  for ( int i = 0 ;
  i < arr . length ;
  i ++ ) {
    if ( ! arr [ i ] ) {
      allMatch = false ;
    }
  }
  System . out . println ( allMatch ? "YES" : "NO" ) ;
}

public static void main ( String [ ] args ) { Scanner scanner = new Scanner ( System . in ) ; StringTokenizer tokenizer = new StringTokenizer ( scanner . nextLine ( ) ) ; int n = Integer . parseInt ( tokenizer . nextToken ( ) ) ; int m = Integer . parseInt ( tokenizer . nextToken ( ) ) ; boolean [ ] arr = new boolean [ m ] ; for ( int i = 0 ; i < n ; i ++ ) { StringTokenizer lineTok = new StringTokenizer ( scanner . nextLine ( ) ) ; int r = Integer . parseInt ( lineTok . nextToken ( ) ) ; for ( int j = 0 ; j < r ; j ++ ) { int i1 = Integer . parseInt ( lineTok . nextToken ( ) ) ; arr [ i1 - 1 ] = true ; } } boolean allMatch = true ; for ( int i = 0 ; i < arr . length ; i ++ ) { if ( ! arr [ i ] ) { allMatch = false ; } } System . out . println ( allMatch ? " YES " : " NO " ) ; }
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