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

    static long layerTotal(int N) {
        if(N == 0) return 1;
        else return 2*layerTotal(N-1) + 3;
    }

    static long pattyTotal(int N) {
        if(N == 0) return 1;
        else return 2*pattyTotal(N-1) + 1;
    }

    static long eatPatty(long X, int N) {
        if(N == 0) 
            return 1;
        else {
            if(X == 1) 
                return 0;
            else if(1 < X && X <= layerTotal(N-1)+1) 
                return eatPatty(X-1, N-1);
            else if(X == 2+layerTotal(N-1)) 
                return pattyTotal(N-1) + 1;
            else if(2+layerTotal(N-1) < X && X <= 2*layerTotal(N-1)+2) 
                return pattyTotal(N-1) + 1 + eatPatty(X-2-layerTotal(N-1), N-1);
            else 
                return 2*pattyTotal(N-1) + 1;
        }
    }
}