output_description: Print `YES` if you can sort p in ascending order in the way stated in the
  problem statement, and `NO` otherwise.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
      p_1 p_2 ... p_N
attempt: n, d = map(int, input().split())
  a = (2 * d) + 1
  if n % a == 0:
      print(int(n / a))
  else:
      print((n // a) + 1)
  
problem_description: Statement
  
  We have a sequence p = {p_1,\ p_2,\ ...,\ p_N} which is a permutation of {1,\
  2,\ ...,\ N}.
  
  You can perform the following operation at most once: choose integers i and j
  (1 \leq i < j \leq N), and swap p_i and p_j. Note that you can also choose not
  to perform it.
  
  Print `YES` if you can sort p in ascending order in this way, and `NO`
  otherwise.
samples: [{"input": "5\n    5 2 3 4 1", "output": "YES\n    \n\nYou can sort p in ascending order by swapping p_1 and p_5.\n\n* * *"}, {"input": "5\n    2 4 3 5 1", "output": "NO\n    \n\nIn this case, swapping any two elements does not sort p in ascending order.\n\n* * *"}, {"input": "7\n    1 2 3 4 5 6 7", "output": "YES\n    \n\np is already sorted in ascending order, so no operation is needed."}]