public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  int [ ] arr = new int [ n ] ;
  int max = 0 ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    arr [ i ] = sc . nextInt ( ) ;
    max = Math . max ( max , arr [ i ] ) ;
  }
  boolean [ ] bool = new boolean [ max + 1 ] ;
  int [ ] indicies = new int [ max + 1 ] ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    if ( bool [ arr [ i ] ] == false ) {
      bool [ arr [ i ] ] = true ;
      indicies [ arr [ i ] ] = i ;
    }
    else {
      arr [ indicies [ arr [ i ] ] ] = - 1 ;
      indicies [ arr [ i ] ] = i ;
    }
  }
  int counter = 0 ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    if ( arr [ i ] != - 1 ) {
      counter ++ ;
    }
  }
  System . out . println ( counter ) ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    if ( arr [ i ] != - 1 ) {
      System . out . print ( arr [ i ] + " " ) ;
    }
  }
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; int [ ] arr = new int [ n ] ; int max = 0 ; for ( int i = 0 ; i < n ; i ++ ) { arr [ i ] = sc . nextInt ( ) ; max = Math . max ( max , arr [ i ] ) ; } boolean [ ] bool = new boolean [ max + 1 ] ; int [ ] indicies = new int [ max + 1 ] ; for ( int i = 0 ; i < n ; i ++ ) { if ( bool [ arr [ i ] ] == false ) { bool [ arr [ i ] ] = true ; indicies [ arr [ i ] ] = i ; } else { arr [ indicies [ arr [ i ] ] ] = - 1 ; indicies [ arr [ i ] ] = i ; } } int counter = 0 ; for ( int i = 0 ; i < n ; i ++ ) { if ( arr [ i ] != - 1 ) { counter ++ ; } } System . out . println ( counter ) ; for ( int i = 0 ; i < n ; i ++ ) { if ( arr [ i ] != - 1 ) { System . out . print ( arr [ i ] + " ▁ " ) ; } } }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier)))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (identifier))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (array_access array: (identifier) index: (identifier)))))))) (local_variable_declaration type: (array_type element: (boolean_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (boolean_type) dimensions: (dimensions_expr (binary_expression left: (identifier) right: (decimal_integer_literal)))))) (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (binary_expression left: (identifier) right: (decimal_integer_literal)))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (array_access array: (identifier) index: (array_access array: (identifier) index: (identifier))) right: (false))) consequence: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (array_access array: (identifier) index: (identifier))) right: (true))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (array_access array: (identifier) index: (identifier))) right: (identifier)))) alternative: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (array_access array: (identifier) index: (array_access array: (identifier) index: (identifier)))) right: (unary_expression operand: (decimal_integer_literal)))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (array_access array: (identifier) index: (identifier))) right: (identifier))))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (unary_expression operand: (decimal_integer_literal)))) consequence: (block (expression_statement (update_expression (identifier))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier)))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (unary_expression operand: (decimal_integer_literal)))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (string_literal)))))))))))