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 bread_cnt(lev):
      return 2 ** (lev + 1) - 2
  
  
  def patty_cnt(lev):
      return 2 ** (lev + 1) - 1
  
  
  def burger_cnt(lev):
      return 2 ** (lev + 2) - 3
  
  
  def solve(n, x):
      return _solve(n, x, 0)
  
  
  def _solve(n, x, p):
      total_s = burger_cnt(n)
  
      if x == 1:
          return p
      elif 1 < x and x <= (total_s + 1) // 2:
          reach_mid = 1 if x == (total_s + 1) // 2 else 0
          return _solve(n - 1, x - 1 - reach_mid, p + reach_mid)
      elif (total_s + 1) // 2 < x and x < total_s:
          return _solve(n - 1, x - 2 - burger_cnt(n - 1), p + 1 + patty_cnt(n - 1))
      elif x == total_s:
          return p + patty_cnt(n)
  
  
  n, x = map(int, input().split(" "))
  print(solve(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."}]