$ ghci Fruits.hs 
GHCi, version 8.2.1: http://www.haskell.org/ghc/  :? for help
[1 of 1] Compiling Main             ( Fruits.hs, interpreted )
Ok, 1 module loaded.
*Main> sat fruits 
Unknown.
  Reason: smt tactic failed to show goal to be sat/unsat (incomplete (theory arithmetic))