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 long[] pattyCounts = new long[51];
	static long[] burgerLengths = new long[51];
	static long layers;
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		layers = in.nextLong();
		for( int i = 0; i <= 50; i++ ) {
			pattyCounts[i] = pattyCount(i);
		}
		for( int i = 0; i <= 50; i++ ) {
			burgerLengths[i] = burgerLength(i);
		}
		System.out.println(solve(n, 1, burgerLengths[n]));
	}
	public static long solve(int level, long min, long max) {
		long mid = (max-min)/2 + min;
		if(layers == mid || min == max) {
			//System.out.printf("Base Case: %d Level: %d\n",(long)Math.ceil((double)pattyCounts[level]/2),pattyCounts[level]);
			if( layers >= mid ) return (long) Math.ceil((double)pattyCounts[level]/2);
			else return 0;
		} else if(layers > mid) {
			//System.out.printf("Greater Case: %d\n", pattyCounts[level-1]);
			return (long) pattyCounts[level-1] + 1 + solve( level-1, mid+1, max-1 );
		} else {
			return solve( level-1, min+1, mid-1 );
		}
	}
	public static long pattyCount(int n) {
		if( n == 0 ) return 1;
		return pattyCount(n-1)*2 + 1;
	}
	public static long burgerLength(int n) {
		if( n == 0 ) return 1;
		return burgerLength(n-1)*2 + 3;
	}
}

// BPPPB
// BBPPPBPBPPPBB
// 0012334456777
// 1234567890123
// 2