output_description: If S(N) divides N, print `Yes`; if it does not, print `No`.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
attempt: import sys, collections, math
  
  sys.setrecursionlimit(10**7)
  
  
  def Is():
      return [int(x) for x in sys.stdin.readline().split()]
  
  
  def Ss():
      return sys.stdin.readline().split()
  
  
  def I():
      return int(sys.stdin.readline())
  
  
  def S():
      return input()
  
  
  n, k = Is()
  ls = Is()
  _1 = ls.index(1)
  if _1 < k - 1:
      _1 = k - 1
  elif _1 < n - k:
      _1 = n - k
  print(math.ceil(_1 / (k - 1)) + math.ceil((n - 1 - _1) / (k - 1)))
  
problem_description: Statement
  
  Let S(n) denote the sum of the digits in the decimal notation of n. For
  example, S(101) = 1 + 0 + 1 = 2.
  
  Given an integer N, determine if S(N) divides N.
samples: [{"input": "12", "output": "Yes\n    \n\nIn this input, N=12. As S(12) = 1 + 2 = 3, S(N) divides N.\n\n* * *"}, {"input": "101", "output": "No\n    \n\nAs S(101) = 1 + 0 + 1 = 2, S(N) does not divide N.\n\n* * *"}, {"input": "999999999", "output": "Yes"}]