(define (bottles n)
  (display
   (string-append 
    (cond ((= n 0) "No more bottles")
          ((= n 1) "One bottle")
          (else (string-append (number->string n) " bottles"))) " of beer")))

(define (beer n)
  (if (> n 0)
      (begin
        (bottles n) (display " on the wall") (newline)
        (bottles n) (newline)
        (display "Take one down, pass it around") (newline)
        (bottles (- n 1)) (display " on the wall") (newline)
        (newline)
        (beer (- n 1))
        )      
      null
      )
  )

(beer 99)