public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  int [ ] parents = new int [ n ] ;
  int [ ] k = new int [ n ] ;
  LinkedList < Integer > hotels = new LinkedList < > ( ) ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    if ( sc . nextInt ( ) == 1 ) {
      hotels . add ( i ) ;
    }
  }
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    parents [ i ] = sc . nextInt ( ) - 1 ;
    if ( parents [ i ] != - 1 ) {
      k [ parents [ i ] ] ++ ;
    }
  }
  LinkedList < Integer > bestPath = null ;
  for ( int h : hotels ) {
    LinkedList < Integer > path = new LinkedList < > ( ) ;
    path . addFirst ( h ) ;
    while ( true ) {
      int prev = parents [ path . getFirst ( ) ] ;
      if ( prev == - 1 ) {
        break ;
      }
      if ( k [ prev ] > 1 ) {
        break ;
      }
      path . addFirst ( prev ) ;
    }
    if ( bestPath == null || bestPath . size ( ) < path . size ( ) ) {
      bestPath = path ;
    }
  }
  System . out . println ( bestPath . size ( ) ) ;
  for ( int v : bestPath ) {
    System . out . print ( v + 1 + " " ) ;
  }
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; int [ ] parents = new int [ n ] ; int [ ] k = new int [ n ] ; LinkedList < Integer > hotels = new LinkedList < > ( ) ; for ( int i = 0 ; i < n ; i ++ ) { if ( sc . nextInt ( ) == 1 ) { hotels . add ( i ) ; } } for ( int i = 0 ; i < n ; i ++ ) { parents [ i ] = sc . nextInt ( ) - 1 ; if ( parents [ i ] != - 1 ) { k [ parents [ i ] ] ++ ; } } LinkedList < Integer > bestPath = null ; for ( int h : hotels ) { LinkedList < Integer > path = new LinkedList < > ( ) ; path . addFirst ( h ) ; while ( true ) { int prev = parents [ path . getFirst ( ) ] ; if ( prev == - 1 ) { break ; } if ( k [ prev ] > 1 ) { break ; } path . addFirst ( prev ) ; } if ( bestPath == null || bestPath . size ( ) < path . size ( ) ) { bestPath = path ; } } System . out . println ( bestPath . size ( ) ) ; for ( int v : bestPath ) { System . out . print ( v + 1 + " ▁ " ) ; } }
(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: (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: (generic_type (type_identifier) (type_arguments (type_identifier))) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (generic_type (type_identifier) (type_arguments)) arguments: (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: (identifier)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal))) consequence: (block (expression_statement (method_invocation object: (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 (expression_statement (assignment_expression left: (array_access array: (identifier) index: (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: (array_access array: (identifier) index: (identifier)) right: (unary_expression operand: (decimal_integer_literal)))) consequence: (block (expression_statement (update_expression (array_access array: (identifier) index: (array_access array: (identifier) index: (identifier))))))))) (local_variable_declaration type: (generic_type (type_identifier) (type_arguments (type_identifier))) declarator: (variable_declarator name: (identifier) value: (null_literal))) (enhanced_for_statement type: (integral_type) name: (identifier) value: (identifier) body: (block (local_variable_declaration type: (generic_type (type_identifier) (type_arguments (type_identifier))) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (generic_type (type_identifier) (type_arguments)) arguments: (argument_list)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) (while_statement condition: (parenthesized_expression (true)) body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (array_access array: (identifier) index: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (unary_expression operand: (decimal_integer_literal)))) consequence: (block (break_statement))) (if_statement condition: (parenthesized_expression (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (decimal_integer_literal))) consequence: (block (break_statement))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (null_literal)) right: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (identifier))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))) (enhanced_for_statement type: (integral_type) name: (identifier) value: (identifier) body: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (string_literal)))))))))