output_description: Print the number of patties in the bottom-most X layers from the bottom of a
  level-N burger.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N X
attempt: def getItemCount(L):
      if L == 0:
          return 1
      return 2 * getItemCount(L - 1) + 3
  
  
  def getPatsCount(L, eaten):
      if eaten * 2 - 1 == getItemCount(L):
          return 2 ** (1 + layer) + 1
      return 2 ** (1 + layer)
  
  
  def getAns(layer, eaten):
      items = getItemCount(layer)
      patsInLayer = getPatsCount(layer, eaten)
      if layer == 0 and eaten == 1:
          return 1
      if eaten == items:
          return patsInLayer
      elif eaten < items:
          return getAns(layer - 1, eaten - 1)
      else:
          return patsInLayer + getAns(layer - 1, eaten - 1)
  
  
  layer, eaten = [int(x) for x in input().split()]
  print(getAns(layer, eaten))
  
  """
  tPats = 0
  if layer != 0:
    while 1:
      items = getItemCount(layer)
      patsInLayer = getPatsCount(layer)
  
      if eaten == items:
        if layer != 0:
          tPats += patsInLayer
          eaten -= items
        break
      elif eaten < items:
        eaten -= 1
      elif eaten > items:
        tPats += patsInLayer + 1
        eaten -= items
      layer -= 1
      if layer < 0:
        break
  else:
    if eaten == 1:
      print(1)
    else:
      print(0)
  print(tPats)
  """
  
problem_description: Statement
  
  In some other world, today is Christmas.
  
  Mr. Takaha decides to make a multi-dimensional burger in his party. A _level-
  L burger_ (L is an integer greater than or equal to 0) is the following thing:
  
    * A level-0 burger is a patty.
    * A level-L burger (L \geq 1) is a bun, a level-(L-1) burger, a patty, another level-(L-1) burger and another bun, stacked vertically in this order from the bottom.
  
  For example, a level-1 burger and a level-2 burger look like `BPPPB` and
  `BBPPPBPBPPPBB` (rotated 90 degrees), where `B` and `P` stands for a bun and a
  patty.
  
  The burger Mr. Takaha will make is a level-N burger. Lunlun the Dachshund will
  eat X layers from the bottom of this burger (a layer is a patty or a bun). How
  many patties will she eat?
samples: [{"input": "2 7", "output": "4\n    \n\nThere are 4 patties in the bottom-most 7 layers of a level-2 burger\n(`BBPPPBPBPPPBB`).\n\n* * *"}, {"input": "1 1", "output": "0\n    \n\nThe bottom-most layer of a level-1 burger is a bun.\n\n* * *"}, {"input": "50 4321098765432109", "output": "2160549382716056\n    \n\nA level-50 burger is rather thick, to the extent that the number of its layers\ndoes not fit into a 32-bit integer."}]