class Solution:
  def sort(self, arr):
    sortedVersion = sorted(arr)
    left, right = 0, len(arr)-1

    while left < len(arr) and arr[left] == sortedVersion[left]:
      left += 1
    while right >= 0 and arr[right] == sortedVersion[right]:
      right -= 1
    
    if left >= right: # if it's already sorted
      return 0

    count = right - left + 1
    return count