from Solution import Solution 
sol = Solution()

assert(sol.countElements([1,2,3]) == 2)
assert(sol.countElements([1,1,3,3,5,5,7,7]) == 0)
assert(sol.countElements([1,3,2,3,5,0]) == 3)
assert(sol.countElements([1,1, 2, 2]) == 2)