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: n, k = map(int, input().split())
  
  cnt = [0, 1]
  tmp = [[0, 1]]
  
  for i in range(n):
  
      tmp.append([cnt[0] * 2 + 2, cnt[1] * 2 + 1])
      cnt[0] = cnt[0] * 2 + 2
      cnt[1] = cnt[1] * 2 + 1
  
  """
  半分に区切ってジャスト半分なら前の分+1を出力
  大きければ前の分+1を足して次
  小さければ数える数を1小さくしてレベルを下げる
  """
  num = 0
  for i in range(n, 0, -1):
      if (sum(tmp[i]) + 1) / 2 == k:
          num += tmp[i - 1][1] + 1
          break
      elif (sum(tmp[i]) - 1) / 2 == k:
          num += tmp[i - 1][1]
          break
      elif sum(tmp[i]) == k or sum(tmp[i]) == k:
          num += tmp[i][1]
          break
      elif (sum(tmp[i]) - 1) / 2 < k:
          num += tmp[i - 1][1] + 1
          k = k - sum(tmp[i - 1]) - 2
      elif (sum(tmp[i]) - 1) / 2 > k:
          k = k - 1
  print(num)
  
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."}]