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.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.util.Arrays;

public class Main implements Runnable {

    private int n;
    private long x;
    
    public static void main(String[] args) throws IOException {
        Main c = new Main();
	c.run();
    }

    private void set() {
	try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
	    String[] parts = br.readLine().split("[\\s]+");
	    n = Integer.parseInt(parts[0]);
	    x = Long.parseLong(parts[1]);
	} catch (IOException e) {
	    e.printStackTrace();
	}
    }

    @Override
    public void run() {
	set();
	long[] length = new long[n+1];
	long[] number = new long[n+1];
	length[0] = 1;
	number[0] = 1;
	for (int i=1;i<n+1;i++) {
	    length[i] = 2*length[i-1]+3;
	    number[i] = 2*number[i-1]+1;
	}
	long num = 0;
	long rem = x;
	for (int i=n;i>=0;i--) {
	    if (i == 0) {
		num++;
		break;
	    }
	    
	    if (rem == 1) break;
	    if (rem == length[i]) {
		num += number[i];
		break;
	    }
	    if (rem == length[i-1]+2) {
		num += number[i-1]+1;
		break;
	    }

	    if (rem < length[i-1]+2) {
		rem = rem - 1;
	    } else {
		rem = rem - (length[i-1]+2);
		num += number[i-1]+1;
	    }
	}
	System.out.println(num);
    }

    private long pow(long base,long power) {
	if (power == 0) return 1;
	if (power%2 == 0) {
	    long h = pow(base,power/2);
	    return h*h;
	} else {
	    return base*pow(base,power-1);
	}
    }
}