public static void main ( String [ ] args ) {
  Scanner in = new Scanner ( System . in ) ;
  int n , i , m , ans = 0 , mint ;
  n = in . nextInt ( ) ;
  for ( i = 1 ;
  i <= n ;
  i ++ ) {
    m = in . nextInt ( ) ;
    mint = Math . min ( m - 1 , 1000000 - m ) ;
    ans = Math . max ( ans , mint ) ;
  }
  System . out . println ( ans ) ;
  in . close ( ) ;
}

public static void main ( String [ ] args ) { Scanner in = new Scanner ( System . in ) ; int n , i , m , ans = 0 , mint ; n = in . nextInt ( ) ; for ( i = 1 ; i <= n ; i ++ ) { m = in . nextInt ( ) ; mint = Math . min ( m - 1 , 1000000 - m ) ; ans = Math . max ( ans , mint ) ; } System . out . println ( ans ) ; in . close ( ) ; }
(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)) declarator: (variable_declarator name: (identifier)) declarator: (variable_declarator name: (identifier)) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal)) declarator: (variable_declarator name: (identifier))) (expression_statement (assignment_expression left: (identifier) right: (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 (expression_statement (assignment_expression left: (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 (binary_expression left: (identifier) right: (decimal_integer_literal)) (binary_expression left: (decimal_integer_literal) right: (identifier)))))) (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (identifier))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))