#| BEGIN (Введите свое решение) |#
(define (filtered-accumulate combiner null-value term a next b filter)
  (define (iter a result)
    (if (> a b)
        result
        (iter (next a) (combiner result (if (filter a)
                                            (term a)
                                            null-value)))))
  (iter a null-value))
#| END |#