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 {

	static Scanner scanner;

	static long[] mai;
	static long[] paty;
	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

	    int N=gi();
	    long X=gl();
	    mai=new long[N+1];
	    paty=new long[N+1];
        mai[0]=1;
        paty[0]=1;
	    for(int i=1; i<N+1;i++) {
	    	mai[i]=mai[i-1]*2+3;
	    	paty[i]=paty[i-1]*2+1;
	    }
	    System.out.print(f(N,X));
	}

	public static long f(int n, long x) {
        if(x==0)return 0;
		if(n==0) {
			if(x==0) {
				return 0;
			} else {
				return 1;
			}
		}
		long half=(mai[n]-1)/2;
		if (half<x) {
			return paty[n-1] + 1 + f(n-1, x-half-1);
		} else {
			return f(n-1, x-1);
		}
	}

	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
}