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.*;
import static java.lang.Math.*;
import java.math.BigInteger;

public class Main {

	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		// 入力
		int n = sc.nextInt();
		long x = sc.nextLong();
		
		// 計算
	    long result = dfs(n, x);

		// 出力
		System.out.println(result);
        
	}
	
	public static long pow(long a,long n) {
	    long res=1;
	    while (n>0) {
	        if ((n-n/2*2)==1) {
	            res=(res*a);
	        }
	        a=(a*a);
	        n>>=1;
	    }
	    return res;
	}
	
	public static long len(int n) {
	    return pow(2, n+2) - 3;
	}
	
	public static long p(int n) {
	    return pow(2, n+1) - 1;
	}
	
	public static long dfs(int n, long x) {
	    if(x == 0) return 0;
	    if(n == 0) return 1;
	    long len = len(n-1);
	    if(x <= 1 + len){
	        return dfs(n-1, x-1);
	    }else{
	        return p(n-1) + 1 + dfs(n-1, x-2-len);
	    }
	}
}