numUnique

Write a method numUnique that takes three integers
   as parameters and that returns the number of unique integers among the
   three.  For example, if the following call is made:

        numUnique(18, 3, 4)

   the method should return 3 because the parameters represent 3 different
   numbers (the values 18, 3 and 4).  By contrast, the following call:

        numUnique(6, 6, 6)

   would return 1 because there is only 1 unique number among the three
   parameters (the value 6).  The values passed to your method might appear in
   any order whatsoever, so you cannot assume that duplicate values would
   appear together.  For example, if the following call is made:

        numUnique(7, 31, 7)

   the method should return 2 because there are 2 unique numbers among the
   parameters (the values 7 and 31).

   Write your solution to numUnique below.