If the numbers 1 to 5 are written out in words: one, two, three, four, five, then there are 3 + 3 + 5 + 4 + 4 = 19 letters used in total.
If all the numbers from 1 to 1000 (one thousand) inclusive were written out in words, how many letters would be used?
NOTE: Do not count spaces or hyphens. For example, 342 (three hundred and forty-two) contains 23 letters and 115 (one hundred and fifteen) contains 20 letters. The use of "and" when writing out numbers is in compliance with British usage.

(defun remove-hyphens (str)
  "Removes any hyphens from str"
  (remove #\- str))

(defun remove-spaces (str)
  "Removes any spaces from str"
  (remove #\Space str))

(defun euler-17 ()
  (+ (loop for i from 1 to 1000 sum
         (length (remove-hyphens (remove-spaces 
                                                       (format nil "~R" i)))))
     ;; SBCL does not include the word 'and', so add 
     ;; those letters also
     (* 3 99 9)))