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 in = new Scanner(System.in);
		int n = in.nextInt();
		long x = in.nextLong();
		long[] num_layer = new long[n+1];
		long[] num_paty = new long[n+1];
		num_layer[0] = 1;
		num_paty[0] = 1;
		for(int i=1;i<=n;i++) {
			num_layer[i] = num_layer[i-1]*2 + 3;
			num_paty[i] = num_paty[i-1]*2 + 1;
		}
		long ans = 0;
		int i = n;
		while(i>=1) {
			if(x==num_layer[i-1]*2+3) {
				ans += num_paty[i-1]*2+1;
				break;
			}else if(x>num_layer[i-1]+2) {
				ans += num_paty[i-1]+1;
				x -= num_layer[i-1]+2;
				i--;
			}else if(x==num_layer[i-1]+2) {
				ans += num_paty[i-1]+1;
				break;
			}else if(x==num_layer[i-1]+1) {
				ans += num_paty[i-1];
				break;
			}else {
				x--;
				i--;
			}
		}
		if(i==0 && x==1) ans++; 
		System.out.println(ans);
		in.close();
	}

}
