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?

Constraints

* 1 \leq N \leq 50
* 1 \leq X \leq ( the total number of layers in a level-N burger )
* N and X are integers.

Input

Input is given from Standard Input in the following format:


N X


Output

Print the number of patties in the bottom-most X layers from the bottom of a level-N burger.

Examples

Input

2 7


Output

4


Input

1 1


Output

0


Input

50 4321098765432109


Output

2160549382716056
import java.util.Scanner;

class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    long X = sc.nextLong();
    System.out.println(makeBurger(N,X));
  }




  public static long makeBurger(int N,long X){
    if(N == 0){
      return 1L;
    }else{
      if(X == 1L){
        return 0L;

      }else if(2L <= X && X <= pow(2L,N + 1) - 2L){
        return makeBurger(N - 1,X - 1);

      }else if(X == pow(2L,N + 1) - 1L){
        return pow(2L,N);
       
      }else if(pow(2L,N + 1) <= X && X <= pow(2L,N + 2) - 4L){
        return pow(2L,N) + makeBurger(N - 1,X - pow(2L,N + 1) + 1L);

      }else{
        return pow(2L,N + 1) - 1L;
      }
    }
  }

  public static long pow(long num,int power){
    long number = num;
    for(int i = 0;i < power - 1;i++){
      number *= num;
    }
    return number;
  }
}
