#| BEGIN (Введите свое решение) |#
(define (cont-frac n d k)
  (define (iter counter buff)
    (if (> counter 0)
        (iter (- counter 1) (/ (n counter) (+ (d counter) buff)))
        buff))
  (iter k 0))

(define (e k)
  (+ 2 (cont-frac (lambda (i) 1.0)
           (lambda (i) (cond ((= (remainder (+ i 1) 3) 0)
                                (* (/ (+ i 1) 3) 2))
                             (else 1)))
           k)))
#| END |#