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: using System;
  using System;
  using System.Collections.Generic;
  using System.Linq;
  
  
      class Solver5
      {
          /*
           * 
           * https://atcoder.jp/contests/abc115/tasks/abc115_d
           * 
           */
   public void Solve5()
          {
              var nx = u.readLongArrayBySplit();
  			var n = nx[0];
              var x = nx[1];
              long ans = 0;
  
              while (true)
              {
                  var thk = new long[5]{ 1, (long)Math.Pow(2,n + 1) - 3, 1, (long)Math.Pow(2, n + 1) - 3, 1 };
                  var pc = new long[5] { 0, (long)Math.Pow(2, n ) - 1 , 1, (long)Math.Pow(2, n )- 1, 0 };
                  for (int i = 0; i < 5; i++)
                  {
                      if (x > thk[i])
                      {
                          x -= thk[i];
                          ans += pc[i];
                      }
                      else if (x < thk[i])
                      {
                          n--;
                          break;
                      }
                      else
                      {
                          ans += pc[i];
                          Console.WriteLine(ans.ToString());
                          return;
                      }
                  }
  
              }
  
          }
          static void Main()
          {
              var solver = new Solver5();
              solver.Solve5();
          }
      }
      static class u
      {
        public static long[] readLongArrayBySplit() { return Console.ReadLine().Split(' ').Select(s => long.Parse(s)).ToArray(); }
      }
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."}]