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.*;
import java.io.*;

/*
   AtCoder contests
   coder : yoichion
 */

public class Main {
    public static long total(int level){
        if (level<=0) return 1;
        return 3 + 2 * total(level-1);
    }
    public static long patty(int level){
        if (level<=0) return 1;
        return 1 + 2 * patty(level-1);
    }
    public static long eat(int level, long layer){
        if(layer<=0) return 0;
        if(level==0) return 1;
        if(layer >= total(level)) return patty(level);

        if(layer <= 1 + total(level-1)){
            return eat(level-1, layer-1);
        }
        if(layer == 2 + total(level-1)){
            return 1 + patty(level-1);
        }
        return patty(level-1) + 1 + eat(level-1, layer-total(level-1)-2);
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        long X = sc.nextLong();
        System.out.println(eat(N,X));
    }
}