(defun temperature()

  (terpri)

  (princ "Fahrenheit To Celius Converter")

  (terpri)

  (terpri)

  (princ "Enter Fahrenheit Temperature : ")

  (setq ftemp (read))

  (terpri)

  (setq celsius  (* (- ftemp 32) 5 / 9))

  (princ "The temperature in celsius is  ")

  (write celsius))

  (terpri)

(temperature)