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;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        long x  =  sc.nextLong();

        long ans = 0;
        while (n >= 0) {
            long center = getCenter(n);
            if (n == 0) {
                ans += 1;
                break;
            }
            if (x == getALL(n)) {
                ans += getAllP(n);
                break;
            }
            if (x == 1) {
                break;
            }

            if (x > center) {
                ans += getAllP(n - 1) + 1;
                x -= center;
                n--;
                if (x == 1 && n != 0) {
                    break;
                }
            } else if (x < center) {
                n--;
                x--;

            } else {
                ans += getAllP(n - 1) + 1;
                break;
            }
        }





        System.out.println(ans);
    }

    static long getAllP(int n ) {
        return (long) (Math.pow(2, n + 1) - 1);
    }
    static long getCenter(int n) {
        return (long) (Math.pow(2, n + 1) - 1);
    }
    static long getALL(int n) {
        return (long) (Math.pow(2, n + 2) - 3);
    }

}