(defun main ()
  (destructuring-bind (p q r) (mapcar (lambda (x)
                                        (/ x 100))
                                      (list (read) (read) (read)))
    (let ((*read-default-float-format* 'double-float))
      (write
       (float
        (/ (max (+ p q)
                (+ q r)
                (+ r p))
           (+ p q r)))))))

(main)