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) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		long x = sc.nextLong();
		sc.close();

		if (x <= n) {
			System.out.println(0);
			return;
		}

		long[] pTotal = new long[n + 1];
		pTotal[0] = 1;
		for (int i = 1; i <= n; i++) {
			pTotal[i] = pTotal[i - 1] * 2 + 1;
		}

		long total = (long) Math.pow(2, n + 2) - 3;
		if (total - n <= x) {
			System.out.println(pTotal[n]);
			return;
		}

		int n2 = n;
		long x2 = x;
		long ans = 0;
		while (n2 >= 0) {
			if (n2 == 0) {
				ans += pTotal[n2];
				break;
			}
			long mid = total / 2 + 1;
			n2--;
			if (x2 == mid) {
				ans += pTotal[n2] + 1;
				break;
			}
			if (x2 > mid) {
				ans += pTotal[n2] + 1;
				x2 -= mid;
			} else {
				x2--;
			}
			if (x2 == 0) {
				break;
			}
			total -= mid + 1;
		}
		System.out.println(ans);
	}
}
