public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  Map < Integer , List < Integer >> map = new HashMap < > ( ) ;
  for ( int i = 0 ;
  i < 2 * n ;
  i ++ ) {
    map . computeIfAbsent ( sc . nextInt ( ) , k -> new ArrayList < > ( ) ) . add ( i ) ;
  }
  int [ ] b = new int [ 2 * n ] ;
  int max = 2 * n ;
  int group = 1 ;
  for ( List < Integer > list : map . values ( ) ) {
    if ( list . size ( ) == 1 ) {
      b [ list . get ( 0 ) ] = group ;
      group = 3 - group ;
    }
  }
  for ( List < Integer > list : map . values ( ) ) {
    if ( list . size ( ) > 1 ) {
      for ( int i = 0 ;
      i < list . size ( ) ;
      i ++ ) {
        b [ list . get ( i ) ] = group ;
        group = 3 - group ;
      }
      max -= list . size ( ) - 2 ;
    }
  }
  if ( max % 2 == 0 ) {
    max = max * max / 4 ;
  }
  else {
    max = ( max / 2 ) * ( max / 2 + 1 ) ;
  }
  StringBuilder sb = new StringBuilder ( ) ;
  for ( int i : b ) {
    sb . append ( i ) . append ( " " ) ;
  }
  System . out . println ( max + "\n" + sb ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; Map < Integer , List < Integer > > map = new HashMap < > ( ) ; for ( int i = 0 ; i < 2 * n ; i ++ ) { map . computeIfAbsent ( sc . nextInt ( ) , k -> new ArrayList < > ( ) ) . add ( i ) ; } int [ ] b = new int [ 2 * n ] ; int max = 2 * n ; int group = 1 ; for ( List < Integer > list : map . values ( ) ) { if ( list . size ( ) == 1 ) { b [ list . get ( 0 ) ] = group ; group = 3 - group ; } } for ( List < Integer > list : map . values ( ) ) { if ( list . size ( ) > 1 ) { for ( int i = 0 ; i < list . size ( ) ; i ++ ) { b [ list . get ( i ) ] = group ; group = 3 - group ; } max -= list . size ( ) - 2 ; } } if ( max % 2 == 0 ) { max = max * max / 4 ; } else { max = ( max / 2 ) * ( max / 2 + 1 ) ; } StringBuilder sb = new StringBuilder ( ) ; for ( int i : b ) { sb . append ( i ) . append ( " ▁ " ) ; } System . out . println ( max + " \n " + sb ) ; }
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(argument_list)))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (binary_expression left: (decimal_integer_literal) right: (identifier))) update: (update_expression (identifier)) body: (block (expression_statement (method_invocation object: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) (lambda_expression parameters: (identifier) body: (object_creation_expression type: (generic_type (type_identifier) (type_arguments)) arguments: (argument_list))))) name: (identifier) arguments: (argument_list (identifier)))))) (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: 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(argument_list))) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) right: (identifier))) (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (decimal_integer_literal) right: (identifier)))))) (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal)))))))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (decimal_integer_literal))))) alternative: (block (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)))))))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list)))) (enhanced_for_statement type: (integral_type) name: (identifier) value: (identifier) body: (block (expression_statement (method_invocation object: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) name: (identifier) arguments: (argument_list (string_literal)))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (identifier) right: (string_literal)) right: (identifier)))))))