fog-kreek-challange.rkt~

#lang racket

(require srfi/13) ; string functions

(define letters "acdegilmnoprstuw")
  
(define (unhash v) 
  (_unhash v "")) ; start with empty accu

(define (_unhash v a)
  (let ((index (modulo v 37)))
    (cond ((= v 7) a)
          (true (_unhash (/ (- v index) 37)
                         (string-concatenate `(,(string (string-ref letters index)) ,a)))))))