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 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        long X = sc.nextLong();

        System.out.println(solve(N, X));

        sc.close();
    }

    static long solve(int N, long X) {
        long[] totalNums = new long[N + 1];
        totalNums[0] = 1;
        for (int i = 1; i < totalNums.length; ++i) {
            totalNums[i] = totalNums[i - 1] * 2 + 3;
        }

        long[] pattyNums = new long[N + 1];
        pattyNums[0] = 1;
        for (int i = 1; i < pattyNums.length; ++i) {
            pattyNums[i] = pattyNums[i - 1] * 2 + 1;
        }

        return search(totalNums, pattyNums, N, X);
    }

    static long search(long[] totalNums, long[] pattyNums, int level, long x) {
        if (level == 0) {
            return 1;
        }

        if (x == 1) {
            return 0;
        } else if (x <= totalNums[level - 1] + 1) {
            return search(totalNums, pattyNums, level - 1, x - 1);
        } else if (x == totalNums[level - 1] + 2) {
            return pattyNums[level - 1] + 1;
        } else if (x <= totalNums[level - 1] * 2 + 2) {
            return pattyNums[level - 1] + 1 + search(totalNums, pattyNums, level - 1, x - (totalNums[level - 1] + 2));
        } else {
            return pattyNums[level];
        }
    }
}