# Task
 A range-collapse representation of an array of integers looks like this: `"1,3-6,8"`, where `3-6` denotes the range from `3-6`, i.e. `[3,4,5,6]`. 
 Hence `"1,3-6,8"` = `[1,3,4,5,6,8]`. Some other range-collapse representations of `[1,3,4,5,6,8]` include `"1,3-5,6,8", "1,3,4,5,6,8", etc`.
 Each range is written in the following format `"a-b"`, where `a < b`, and the whole range must belong to the array in an increasing order.
 You are given an array `arr`. Your task is to find the number of different range-collapse representations of the given array.
# Example
 For `arr = [1,3,4,5,6,8]`, the result should be `8`.
 ```
 "1,3-4,5,6,8"
 "1,3-4,5-6,8"
 "1,3-5,6,8"
 "1,3-6,8"
 "1,3,4-5,6,8"
 "1,3,4-6,8"
 "1,3,4,5-6,8"
 "1,3,4,5,6,8"```
# Input/OutPut
 - `[input]` integer array `arr`
  sorted array of different positive integers.
 - `[output]` an integer
  the number of different range-collapse representations of the given array.
descriptions=lambda l:1<<sum(b-a==1for a,b in zip(l,l[1:]))
descriptions=lambda l:1<<sum(b-a==1for a,b in zip(l,l[1:]))