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(final String[] args) {
        final Scanner scanner = new Scanner(System.in);
        final int n = scanner.nextInt();
        final long x = scanner.nextLong();

        System.out.println(recursive(0, n, x));
    }

    private static long recursive(final long answer, final int level, final long point) {
        if (level == 0) {
            return answer + 1;
        }

        final long burger = 4 * (long) Math.pow(2, level) - 3;
        final long patty = 2 * (long) Math.pow(2, level - 1) - 1;

        if (point == 1) {
            return answer;
        }

        if (point == burger) {
            return answer + 2 * patty + 1;
        }

        if (point == (burger + 1) / 2) {
            return answer + patty + 1;
        }

        if (point < (burger + 1) / 2) {
            return recursive(answer, level - 1, point - 1);
        }

        return recursive(answer + patty + 1, level - 1, point - (burger + 1) / 2);
    }
}
