[Haskell-beginners] Storing the time difference between two Monotonic time results

Hello, I am trying to time a function I have written in haskell using the clock package in the following way: *start <- getTime Monotonic* *evaluate(something)* *end <- getTime Monotonic* *fprint (timeSpecs % "\n") start end* Now what I want is to store the time difference between *start* and *end. *Is there a way I can do that? Regards Awsaf