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.*;

public class Main {
	
	static class Burger {
		
		public static long getNumPatties(int level) {
			return pow(2, level+1)-1;
		}
		
		public static long getHeight(int level) {
			return pow(2, level+2)-3;
		}
		
		static long pow(int a, int b) {
			long product = 1;
			while (b > 0) {
				product *= a;
				b--;
			}
			return product;
		}
	}
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		long X = sc.nextLong();
		
		System.out.println(countPatties(N, X));
		
	}
	
	public static long countPatties(int level, long x) {
		if (x == 0) {
			return 0;
		} else if (level == 0) {
			return 1;
		} else if (x >= Burger.getHeight(level) - level) {
			return Burger.getNumPatties(level);
		}
		
		if (x < Burger.getHeight(level-1)+2) {
			return countPatties(level-1, x-1);
		} else {
			return Burger.getNumPatties(level-1)+1+countPatties(level-1, x-Burger.getHeight(level-1)-2);
		}
	}

}
