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.io.InputStream;
import java.io.PrintStream;
import java.util.Scanner;

public class Main {
	InputStream in = System.in;
	PrintStream out = System.out;

	long numOfSou(int level) {
		if (level == 0) {
			return 1;
		} else {
			return 2 * numOfSou(level - 1) + 3;
		}

	}

	long f(int n, long x) {

		if (n == 0 && x == 1) {
			return 1;
		}
		else if (x == 1) {
			return 0;
		}

		long nos = numOfSou(n - 1);

		if (x <= nos + 1) {
			return f(n - 1, x - 1);
		} else if (x == nos + 2) {
			return f(n - 1, nos) + 1;
		} else if (x <= 2 * nos + 2) {
			return f(n - 1, nos) + 1 + f(n - 1, (x - (nos + 2)));
		} else {
			return 2 * f(n - 1, nos) + 1;
		}

	}

	public void _main(String[] args) {
		Scanner sc = new Scanner(in);

		int N = sc.nextInt();
		long X = sc.nextLong();

		sc.close();

		out.println(f(N, X));

	}

	public static void main(String[] args) {
		new Main()._main(args);
	}

}
