How can I compare a string in Racket

(display " Please enter the code : \n")
(define code (read))
(cond
  ((or(string=? code "k")(string=? code "K"))(display "Kid"))
  ((or(string=? code "s")(string=? code "S"))(display "Senior"))
  ( else (display "Adult")))

when running it shows up : string=?: expects type as 1st argument, given: k; other arguments were: "k"