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 java.lang.*;


public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        long x = sc.nextLong();
        long eatp = 0;
        long eati = n;
        boolean th = false;
        for (long i = n; i > 0; i--) {
            if ((eati - i) + Math.pow(2, i + 2) - 3 <= x) {
                eatp += Math.pow(2, i + 1) - 1;
                x -= (eati - i) + Math.pow(2, i + 2) - 3;
                eati = i;
                th = true;
                if (x == 0 || eati == n) {
                    break;
                } else {
                    x--;
                    eatp++;
                }
            }
        }
        if (eati == n && th) {
        }else {
            x -= eati - 1;
            if (x == 2) {
                eatp++;
            } else if (x == 3) {
                eatp += 2;
            } else if (x >= 4) {
                eatp += 3;
            }
        }
        System.out.println(eatp);
    }
}