public static void main ( String [ ] args ) {
  Scanner in = new Scanner ( System . in ) ;
  int n = in . nextInt ( ) , a [ ] = new int [ n ] , i ;
  for ( i = 0 ;
  i < n - 1 ;
  i ++ ) {
    a [ in . nextInt ( ) - 1 ] ++ ;
  }
  in . close ( ) ;
  for ( i = 0 ;
  i < n ;
  i ++ ) {
    if ( a [ i ] == 0 ) System . out . println ( i + 1 ) ;
  }
}

public static void main ( String [ ] args ) { Scanner in = new Scanner ( System . in ) ; int n = in . nextInt ( ) , a [ ] = new int [ n ] , i ; for ( i = 0 ; i < n - 1 ; i ++ ) { a [ in . nextInt ( ) - 1 ] ++ ; } in . close ( ) ; for ( i = 0 ; i < n ; i ++ ) { if ( a [ i ] == 0 ) System . out . println ( i + 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))) declarator: (variable_declarator name: (identifier) dimensions: (dimensions) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (identifier)))) declarator: (variable_declarator name: (identifier))) (for_statement init: (assignment_expression left: (identifier) right: (decimal_integer_literal)) condition: (binary_expression left: (identifier) right: (binary_expression left: (identifier) right: (decimal_integer_literal))) update: (update_expression (identifier)) body: (block (expression_statement (update_expression (array_access array: (identifier) index: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal))))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) (for_statement init: (assignment_expression left: (identifier) right: (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: (decimal_integer_literal))) consequence: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (decimal_integer_literal))))))))))