import math

class Solution:
  def sort(self, arr):
    sorted_arr = sorted(arr)
    if sorted_arr == arr or len(arr) == 1:
      return 0
    l, r = 0, len(arr) - 1
    while l <= r:
      if arr[l] == sorted_arr[l]:      
        l+= 1
      elif arr[r] == sorted_arr[r]:     
        r -= 1
      else:
        break
    return r-l+1