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: len_burger_cache = {}
  
  
  def len_burger(n: int):
      if n == 0:
          return 1
      elif n in len_burger_cache:
          return len_burger_cache[n]
      else:
          tmp = (len_burger(n - 1) * 2) + 3
          len_burger_cache[n] = tmp
          return tmp
  
  
  def gen_burger(n: int):
      if n == 0:
          return "P"
      return "B" + gen_burger(n - 1) + "P" + gen_burger(n - 1) + "B"
  
  
  def culc_eat(n: int, x: int):
      if n == 0:
          return 1
      if n < len_burger(x):
          # 次の次元まで計算すればOK
          return gen_burger(n)[:x].count("P")
      else:
          # 次の次元の計算を行う
          return culc_eat(n - 1, x - 1)
  
  
  # input
  n, x = input().split()
  n = int(n)
  x = int(x)
  
  # gen burger
  print(culc_eat(n, x))
  
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."}]