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.*;
class Main
{
    static long[] p = new long[51], b = new long[51];
    public static void main (String[] args)
    {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        long x = sc.nextLong();
        p[0] = 1;
        b[0] = 1;
        for(int i = 1; i <= 50; i++){
            p[i] = p[i-1] * 2 + 3;
            b[i] = b[i-1] * 2 + 1;
        }
        System.out.println(func(n, x));
    }
    static long func(int n, long x){
        if(n == 0){
            if(x <= 0) return 0;
            else return 1;
        }
        else{
            if(x <= 1) return 0;
            else if(1 < x && x < 2 + p[n-1]) return func(n-1, x-1);
            else if(x == 2 + p[n-1]) return b[n-1] + 1;
            else if(2 + p[n-1] < x && x < 2 * p[n-1] + 3) return b[n-1] + 1 + func(n-1, x - p[n-1] - 2);
            else return 2 * b[n-1] + 1;
        }
    }
}